39     previousSibling = None  variable in Node
104             refChild.previousSibling = newChild
108                 newChild.previousSibling = node
110                 newChild.previousSibling = None
154         newChild.previousSibling = oldChild.previousSibling
156         oldChild.previousSibling = None
157         if newChild.previousSibling:
158             newChild.previousSibling.nextSibling = newChild
160             newChild.nextSibling.previousSibling = newChild
169             oldChild.nextSibling.previousSibling = oldChild.previousSibling
170         if oldChild.previousSibling is not None:
171             oldChild.previousSibling.nextSibling = oldChild.nextSibling
172         oldChild.nextSibling = oldChild.previousSibling = None
188                         child.nextSibling.previousSibling = child.previousSibling
196                         child.nextSibling.previousSibling = node
269         self.previousSibling = None
290         node.previousSibling = last
686         self.nextSibling = self.previousSibling = None
1021         self.previousSibling = self.nextSibling = None
1119         n = self.previousSibling
1123                 n = n.previousSibling
1139         n = self.previousSibling
1142                 next = n.previousSibling
1556     previousSibling = nextSibling = None  variable in Document
1632         oldChild.nextSibling = oldChild.previousSibling = None