88 def has_header(headers, name):  argument
93     for header, value in headers:
98 def header_value(headers, name):  argument
115     result = [value for header, value in headers
122 def remove_header(headers, name):  argument
131     while i < len(headers):
132         if headers[i][0].lower() == name:
133             result = headers[i][1]
134             del headers[i]
139 def replace_header(headers, name, value):  argument
153     while i < len(headers):
154         if headers[i][0].lower() == name:
156             result = headers[i][1]
157             headers[i] = (name, value)
160         headers.append((name, value))
218     headers = [('content-type', 'text/html'),
220     return error_code, headers, body
235         status, headers, body = error_response(
238         start_response(status, headers)