1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Pickle support</title> 5<link rel="stylesheet" href="../../boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../index.html" title="Boost.Python Reference Manual"> 8<link rel="up" href="../topics.html" title="Chapter 8. Topics"> 9<link rel="prev" href="../topics.html" title="Chapter 8. Topics"> 10<link rel="next" href="indexing_support.html" title="Indexing support"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr><td valign="top"><img alt="" width="" height="" src="../../images/boost.png"></td></tr></table> 14<hr> 15<div class="spirit-nav"> 16<a accesskey="p" href="../topics.html"><img src="../../images/prev.png" alt="Prev"></a><a accesskey="u" href="../topics.html"><img src="../../images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../images/home.png" alt="Home"></a><a accesskey="n" href="indexing_support.html"><img src="../../images/next.png" alt="Next"></a> 17</div> 18<div class="section"> 19<div class="titlepage"><div><div><h2 class="title" style="clear: both"> 20<a name="topics.pickle_support"></a><a class="link" href="pickle_support.html" title="Pickle support">Pickle support</a> 21</h2></div></div></div> 22<div class="toc"><dl class="toc"> 23<dt><span class="section"><a href="pickle_support.html#topics.pickle_support.introduction">Introduction</a></span></dt> 24<dt><span class="section"><a href="pickle_support.html#topics.pickle_support.the_pickle_interface">The Pickle 25 Interface</a></span></dt> 26<dt><span class="section"><a href="pickle_support.html#topics.pickle_support.example">Example</a></span></dt> 27<dt><span class="section"><a href="pickle_support.html#topics.pickle_support.pitfall_and_safety_guard">Pitfall 28 and Safety Guard</a></span></dt> 29<dt><span class="section"><a href="pickle_support.html#topics.pickle_support.practical_advice">Practical Advice</a></span></dt> 30<dt><span class="section"><a href="pickle_support.html#topics.pickle_support.light_weight_alternative_pickle_">Light-weight 31 alternative: pickle support implemented in Python</a></span></dt> 32</dl></div> 33<div class="section"> 34<div class="titlepage"><div><div><h3 class="title"> 35<a name="topics.pickle_support.introduction"></a><a class="link" href="pickle_support.html#topics.pickle_support.introduction" title="Introduction">Introduction</a> 36</h3></div></div></div> 37<p> 38 Pickle is a Python module for object serialization, also known as persistence, 39 marshalling, or flattening. 40 </p> 41<p> 42 It is often necessary to save and restore the contents of an object to 43 a file. One approach to this problem is to write a pair of functions that 44 read and write data from a file in a special format. A powerful alternative 45 approach is to use Python's pickle module. Exploiting Python's ability 46 for introspection, the pickle module recursively converts nearly arbitrary 47 Python objects into a stream of bytes that can be written to a file. 48 </p> 49<p> 50 The Boost Python Library supports the pickle module through the interface 51 as described in detail in the <a href="https://docs.python.org/2/library/pickle.html" target="_top">Python 52 Library Reference for pickle</a>. This interface involves the special 53 methods <code class="computeroutput"><span class="identifier">__getinitargs__</span></code>, 54 <code class="computeroutput"><span class="identifier">__getstate__</span></code> and <code class="computeroutput"><span class="identifier">__setstate__</span></code> as described in the following. 55 Note that <code class="computeroutput"><span class="identifier">Boost</span><span class="special">.</span><span class="identifier">Python</span></code> is also fully compatible with 56 Python's cPickle module. 57 </p> 58</div> 59<div class="section"> 60<div class="titlepage"><div><div><h3 class="title"> 61<a name="topics.pickle_support.the_pickle_interface"></a><a class="link" href="pickle_support.html#topics.pickle_support.the_pickle_interface" title="The Pickle Interface">The Pickle 62 Interface</a> 63</h3></div></div></div> 64<p> 65 At the user level, the Boost.Python pickle interface involves three special 66 methods: 67 </p> 68<div class="variablelist"> 69<p class="title"><b></b></p> 70<dl class="variablelist"> 71<dt><span class="term">__getinitargs__</span></dt> 72<dd> 73<p> 74 When an instance of a Boost.Python extension class is pickled, the 75 pickler tests if the instance has a <code class="computeroutput"><span class="identifier">__getinitargs__</span></code> 76 method. This method must return a Python <code class="computeroutput"><span class="identifier">tuple</span></code> 77 (it is most convenient to use a <a class="link" href="../object_wrappers/boost_python_tuple_hpp.html#object_wrappers.boost_python_tuple_hpp.class_tuple" title="Class tuple"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">python</span><span class="special">::</span><span class="identifier">tuple</span></code></a>). When the instance 78 is restored by the unpickler, the contents of this tuple are used 79 as the arguments for the class constructor. 80 </p> 81<p> 82 If <code class="computeroutput"><span class="identifier">__getinitargs__</span></code> 83 is not defined, <code class="computeroutput"><span class="identifier">pickle</span><span class="special">.</span><span class="identifier">load</span></code> 84 will call the constructor (<code class="computeroutput"><span class="identifier">__init__</span></code>) 85 without arguments; i.e., the object must be default-constructible. 86 </p> 87</dd> 88<dt><span class="term">__getstate__</span></dt> 89<dd><p> 90 When an instance of a <code class="computeroutput"><span class="identifier">Boost</span><span class="special">.</span><span class="identifier">Python</span></code> 91 extension class is pickled, the pickler tests if the instance has 92 a <code class="computeroutput"><span class="identifier">__getstate__</span></code> method. 93 This method should return a Python object representing the state 94 of the instance. 95 </p></dd> 96<dt><span class="term">__setstate__</span></dt> 97<dd><p> 98 When an instance of a <code class="computeroutput"><span class="identifier">Boost</span><span class="special">.</span><span class="identifier">Python</span></code> 99 extension class is restored by the unpickler (<code class="computeroutput"><span class="identifier">pickle</span><span class="special">.</span><span class="identifier">load</span></code>), 100 it is first constructed using the result of <code class="computeroutput"><span class="identifier">__getinitargs__</span></code> 101 as arguments (see above). Subsequently the unpickler tests if the 102 new instance has a <code class="computeroutput"><span class="identifier">__setstate__</span></code> 103 method. If so, this method is called with the result of <code class="computeroutput"><span class="identifier">__getstate__</span></code> (a Python object) 104 as the argument. 105 </p></dd> 106</dl> 107</div> 108<p> 109 The three special methods described above may be <code class="computeroutput"><span class="special">.</span><span class="identifier">def</span><span class="special">()</span></code>'ed 110 individually by the user. However, <code class="computeroutput"><span class="identifier">Boost</span><span class="special">.</span><span class="identifier">Python</span></code> 111 provides an easy to use high-level interface via the <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">python</span><span class="special">::</span><span class="identifier">pickle_suite</span></code> 112 class that also enforces consistency: <code class="computeroutput"><span class="identifier">__getstate__</span></code> 113 and <code class="computeroutput"><span class="identifier">__setstate__</span></code> must be 114 defined as pairs. Use of this interface is demonstrated by the following 115 examples. 116 </p> 117</div> 118<div class="section"> 119<div class="titlepage"><div><div><h3 class="title"> 120<a name="topics.pickle_support.example"></a><a class="link" href="pickle_support.html#topics.pickle_support.example" title="Example">Example</a> 121</h3></div></div></div> 122<div class="toc"><dl class="toc"> 123<dt><span class="section"><a href="pickle_support.html#topics.pickle_support.example.pickle1_cpp">pickle1.cpp</a></span></dt> 124<dt><span class="section"><a href="pickle_support.html#topics.pickle_support.example.pickle2_cpp">pickle2.cpp</a></span></dt> 125<dt><span class="section"><a href="pickle_support.html#topics.pickle_support.example.pickle3_cpp">pickle3.cpp</a></span></dt> 126</dl></div> 127<p> 128 There are three files in <code class="computeroutput"><span class="identifier">python</span><span class="special">/</span><span class="identifier">test</span></code> 129 that show how to provide pickle support. 130 </p> 131<div class="section"> 132<div class="titlepage"><div><div><h4 class="title"> 133<a name="topics.pickle_support.example.pickle1_cpp"></a><a class="link" href="pickle_support.html#topics.pickle_support.example.pickle1_cpp" title="pickle1.cpp">pickle1.cpp</a> 134</h4></div></div></div> 135<p> 136 The C++ class in this example can be fully restored by passing the appropriate 137 argument to the constructor. Therefore it is sufficient to define the 138 pickle interface method <code class="computeroutput"><span class="identifier">__getinitargs__</span></code>. 139 This is done in the following way: Definition of the C++ pickle function: 140 </p> 141<pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">world_pickle_suite</span> <span class="special">:</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">python</span><span class="special">::</span><span class="identifier">pickle_suite</span> 142<span class="special">{</span> 143 <span class="keyword">static</span> 144 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">python</span><span class="special">::</span><span class="identifier">tuple</span> 145 <span class="identifier">getinitargs</span><span class="special">(</span><span class="identifier">world</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">w</span><span class="special">)</span> 146 <span class="special">{</span> 147 <span class="keyword">return</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">python</span><span class="special">::</span><span class="identifier">make_tuple</span><span class="special">(</span><span class="identifier">w</span><span class="special">.</span><span class="identifier">get_country</span><span class="special">());</span> 148 <span class="special">}</span> 149<span class="special">};</span> 150</pre> 151<p> 152 Establishing the Python binding: 153 </p> 154<pre class="programlisting"><span class="identifier">class_</span><span class="special"><</span><span class="identifier">world</span><span class="special">>(</span><span class="string">"world"</span><span class="special">,</span> <span class="identifier">args</span><span class="special"><</span><span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">&>())</span> 155 <span class="comment">// ...</span> 156 <span class="special">.</span><span class="identifier">def_pickle</span><span class="special">(</span><span class="identifier">world_pickle_suite</span><span class="special">())</span> 157 <span class="comment">// ...</span> 158</pre> 159</div> 160<div class="section"> 161<div class="titlepage"><div><div><h4 class="title"> 162<a name="topics.pickle_support.example.pickle2_cpp"></a><a class="link" href="pickle_support.html#topics.pickle_support.example.pickle2_cpp" title="pickle2.cpp">pickle2.cpp</a> 163</h4></div></div></div> 164<p> 165 The C++ class in this example contains member data that cannot be restored 166 by any of the constructors. Therefore it is necessary to provide the 167 <code class="computeroutput"><span class="identifier">__getstate__</span></code>/<code class="computeroutput"><span class="identifier">__setstate__</span></code> pair of pickle interface 168 methods: 169 </p> 170<p> 171 Definition of the C++ pickle functions: 172 </p> 173<pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">world_pickle_suite</span> <span class="special">:</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">python</span><span class="special">::</span><span class="identifier">pickle_suite</span> 174 <span class="special">{</span> 175 <span class="keyword">static</span> 176 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">python</span><span class="special">::</span><span class="identifier">tuple</span> 177 <span class="identifier">getinitargs</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">world</span><span class="special">&</span> <span class="identifier">w</span><span class="special">)</span> 178 <span class="special">{</span> 179 <span class="comment">// ...</span> 180 <span class="special">}</span> 181 182 <span class="keyword">static</span> 183 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">python</span><span class="special">::</span><span class="identifier">tuple</span> 184 <span class="identifier">getstate</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">world</span><span class="special">&</span> <span class="identifier">w</span><span class="special">)</span> 185 <span class="special">{</span> 186 <span class="comment">// ...</span> 187 <span class="special">}</span> 188 189 <span class="keyword">static</span> 190 <span class="keyword">void</span> 191 <span class="identifier">setstate</span><span class="special">(</span><span class="identifier">world</span><span class="special">&</span> <span class="identifier">w</span><span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">python</span><span class="special">::</span><span class="identifier">tuple</span> <span class="identifier">state</span><span class="special">)</span> 192 <span class="special">{</span> 193 <span class="comment">// ...</span> 194 <span class="special">}</span> 195 <span class="special">};</span> 196</pre> 197<p> 198 Establishing the Python bindings for the entire suite: 199 </p> 200<pre class="programlisting"><span class="identifier">class_</span><span class="special"><</span><span class="identifier">world</span><span class="special">>(</span><span class="string">"world"</span><span class="special">,</span> <span class="identifier">args</span><span class="special"><</span><span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">&>())</span> 201 <span class="comment">// ...</span> 202 <span class="special">.</span><span class="identifier">def_pickle</span><span class="special">(</span><span class="identifier">world_pickle_suite</span><span class="special">())</span> 203 <span class="comment">// ...</span> 204</pre> 205<p> 206 For simplicity, the <code class="computeroutput"><span class="identifier">__dict__</span></code> 207 is not included in the result of <code class="computeroutput"><span class="identifier">__getstate__</span></code>. 208 This is not generally recommended, but a valid approach if it is anticipated 209 that the object's <code class="computeroutput"><span class="identifier">__dict__</span></code> 210 will always be empty. Note that the safety guard described below will 211 catch the cases where this assumption is violated. 212 </p> 213</div> 214<div class="section"> 215<div class="titlepage"><div><div><h4 class="title"> 216<a name="topics.pickle_support.example.pickle3_cpp"></a><a class="link" href="pickle_support.html#topics.pickle_support.example.pickle3_cpp" title="pickle3.cpp">pickle3.cpp</a> 217</h4></div></div></div> 218<p> 219 This example is similar to pickle2.cpp. However, the object's <code class="computeroutput"><span class="identifier">__dict__</span></code> is included in the result 220 of <code class="computeroutput"><span class="identifier">__getstate__</span></code>. This 221 requires a little more code but is unavoidable if the object's <code class="computeroutput"><span class="identifier">__dict__</span></code> is not always empty. 222 </p> 223</div> 224</div> 225<div class="section"> 226<div class="titlepage"><div><div><h3 class="title"> 227<a name="topics.pickle_support.pitfall_and_safety_guard"></a><a class="link" href="pickle_support.html#topics.pickle_support.pitfall_and_safety_guard" title="Pitfall and Safety Guard">Pitfall 228 and Safety Guard</a> 229</h3></div></div></div> 230<p> 231 The pickle protocol described above has an important pitfall that the end 232 user of a Boost.Python extension module might not be aware of: 233 </p> 234<p> 235 <span class="bold"><strong><code class="computeroutput"><span class="identifier">__getstate__</span></code> 236 is defined and the instance's <code class="computeroutput"><span class="identifier">__dict__</span></code> 237 is not empty.</strong></span> 238 </p> 239<p> 240 The author of a <code class="computeroutput"><span class="identifier">Boost</span><span class="special">.</span><span class="identifier">Python</span></code> extension class might provide 241 a <code class="computeroutput"><span class="identifier">__getstate__</span></code> method without 242 considering the possibilities that: * his class is used in Python as a 243 base class. Most likely the <code class="computeroutput"><span class="identifier">__dict__</span></code> 244 of instances of the derived class needs to be pickled in order to restore 245 the instances correctly. * the user adds items to the instance's <code class="computeroutput"><span class="identifier">__dict__</span></code> directly. Again, the <code class="computeroutput"><span class="identifier">__dict__</span></code> of the instance then needs to 246 be pickled. 247 </p> 248<p> 249 To alert the user to this highly unobvious problem, a safety guard is provided. 250 If <code class="computeroutput"><span class="identifier">__getstate__</span></code> is defined 251 and the instance's <code class="computeroutput"><span class="identifier">__dict__</span></code> 252 is not empty, <code class="computeroutput"><span class="identifier">Boost</span><span class="special">.</span><span class="identifier">Python</span></code> tests if the class has an attribute 253 <code class="computeroutput"><span class="identifier">__getstate_manages_dict__</span></code>. 254 An exception is raised if this attribute is not defined: 255 </p> 256<pre class="programlisting"><span class="identifier">RuntimeError</span><span class="special">:</span> <span class="identifier">Incomplete</span> <span class="identifier">pickle</span> <span class="identifier">support</span> <span class="special">(</span><span class="identifier">__getstate_manages_dict__</span> <span class="keyword">not</span> <span class="identifier">set</span><span class="special">)</span> 257</pre> 258<p> 259 To resolve this problem, it should first be established that the <code class="computeroutput"><span class="identifier">__getstate__</span></code> and <code class="computeroutput"><span class="identifier">__setstate__</span></code> 260 methods manage the instances's <code class="computeroutput"><span class="identifier">__dict__</span></code> 261 correctly. Note that this can be done either at the C++ or the Python level. 262 Finally, the safety guard should intentionally be overridden. E.g. in C++ 263 (from pickle3.cpp): 264 </p> 265<pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">world_pickle_suite</span> <span class="special">:</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">python</span><span class="special">::</span><span class="identifier">pickle_suite</span> 266<span class="special">{</span> 267 <span class="comment">// ...</span> 268 269 <span class="keyword">static</span> <span class="keyword">bool</span> <span class="identifier">getstate_manages_dict</span><span class="special">()</span> <span class="special">{</span> <span class="keyword">return</span> <span class="keyword">true</span><span class="special">;</span> <span class="special">}</span> 270<span class="special">};</span> 271</pre> 272<p> 273 Alternatively in Python: 274 </p> 275<pre class="programlisting"><span class="identifier">import</span> <span class="identifier">your_bpl_module</span> 276<span class="keyword">class</span> <span class="identifier">your_class</span><span class="special">(</span><span class="identifier">your_bpl_module</span><span class="special">.</span><span class="identifier">your_class</span><span class="special">):</span> 277 <span class="identifier">__getstate_manages_dict__</span> <span class="special">=</span> <span class="number">1</span> 278 <span class="identifier">def</span> <span class="identifier">__getstate__</span><span class="special">(</span><span class="identifier">self</span><span class="special">):</span> 279 <span class="preprocessor"># your</span> <span class="identifier">code</span> <span class="identifier">here</span> 280 <span class="identifier">def</span> <span class="identifier">__setstate__</span><span class="special">(</span><span class="identifier">self</span><span class="special">,</span> <span class="identifier">state</span><span class="special">):</span> 281 <span class="preprocessor"># your</span> <span class="identifier">code</span> <span class="identifier">here</span> 282</pre> 283</div> 284<div class="section"> 285<div class="titlepage"><div><div><h3 class="title"> 286<a name="topics.pickle_support.practical_advice"></a><a class="link" href="pickle_support.html#topics.pickle_support.practical_advice" title="Practical Advice">Practical Advice</a> 287</h3></div></div></div> 288<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 289<li class="listitem"> 290 In <code class="computeroutput"><span class="identifier">Boost</span><span class="special">.</span><span class="identifier">Python</span></code> extension modules with many 291 extension classes, providing complete pickle support for all classes 292 would be a significant overhead. In general complete pickle support 293 should only be implemented for extension classes that will eventually 294 be pickled. 295 </li> 296<li class="listitem"> 297 Avoid using <code class="computeroutput"><span class="identifier">__getstate__</span></code> 298 if the instance can also be reconstructed by way of <code class="computeroutput"><span class="identifier">__getinitargs__</span></code>. 299 This automatically avoids the pitfall described above. 300 </li> 301<li class="listitem"> 302 If <code class="computeroutput"><span class="identifier">__getstate__</span></code> is 303 required, include the instance's <code class="computeroutput"><span class="identifier">__dict__</span></code> 304 in the Python object that is returned. 305 </li> 306</ul></div> 307</div> 308<div class="section"> 309<div class="titlepage"><div><div><h3 class="title"> 310<a name="topics.pickle_support.light_weight_alternative_pickle_"></a><a class="link" href="pickle_support.html#topics.pickle_support.light_weight_alternative_pickle_" title="Light-weight alternative: pickle support implemented in Python">Light-weight 311 alternative: pickle support implemented in Python</a> 312</h3></div></div></div> 313<p> 314 The pickle4.cpp example demonstrates an alternative technique for implementing 315 pickle support. First we direct Boost.Python via the class_::enable_pickling() 316 member function to define only the basic attributes required for pickling: 317 </p> 318<pre class="programlisting"><span class="identifier">class_</span><span class="special"><</span><span class="identifier">world</span><span class="special">>(</span><span class="string">"world"</span><span class="special">,</span> <span class="identifier">args</span><span class="special"><</span><span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">&>())</span> 319 <span class="comment">// ...</span> 320 <span class="special">.</span><span class="identifier">enable_pickling</span><span class="special">()</span> 321 <span class="comment">// ...</span> 322</pre> 323<p> 324 This enables the standard Python pickle interface as described in the Python 325 documentation. By "injecting" a <code class="computeroutput"><span class="identifier">__getinitargs__</span></code> 326 method into the definition of the wrapped class we make all instances pickleable: 327 </p> 328<pre class="programlisting"><span class="preprocessor"># import</span> <span class="identifier">the</span> <span class="identifier">wrapped</span> <span class="identifier">world</span> <span class="keyword">class</span> 329<span class="identifier">from</span> <span class="identifier">pickle4_ext</span> <span class="identifier">import</span> <span class="identifier">world</span> 330 331<span class="preprocessor"># definition</span> <span class="identifier">of</span> <span class="identifier">__getinitargs__</span> 332<span class="identifier">def</span> <span class="identifier">world_getinitargs</span><span class="special">(</span><span class="identifier">self</span><span class="special">):</span> 333 <span class="keyword">return</span> <span class="special">(</span><span class="identifier">self</span><span class="special">.</span><span class="identifier">get_country</span><span class="special">(),)</span> 334 335<span class="preprocessor"># now</span> <span class="identifier">inject</span> <span class="identifier">__getinitargs__</span> <span class="special">(</span><span class="identifier">Python</span> <span class="identifier">is</span> <span class="identifier">a</span> <span class="identifier">dynamic</span> <span class="identifier">language</span><span class="special">!)</span> 336<span class="identifier">world</span><span class="special">.</span><span class="identifier">__getinitargs__</span> <span class="special">=</span> <span class="identifier">world_getinitargs</span> 337</pre> 338<p> 339 See also the tutorial section on injecting additional methods from Python. 340 </p> 341</div> 342</div> 343<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 344<td align="left"></td> 345<td align="right"><div class="copyright-footer">Copyright © 2002-2005, 2015 David Abrahams, Stefan Seefeld<p> 346 Distributed under the Boost Software License, Version 1.0. (See accompanying 347 file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a> 348 </p> 349</div></td> 350</tr></table> 351<hr> 352<div class="spirit-nav"> 353<a accesskey="p" href="../topics.html"><img src="../../images/prev.png" alt="Prev"></a><a accesskey="u" href="../topics.html"><img src="../../images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../images/home.png" alt="Home"></a><a accesskey="n" href="indexing_support.html"><img src="../../images/next.png" alt="Next"></a> 354</div> 355</body> 356</html> 357
