code: def render_field(parser, token):
      
      error_msg = '%r tag requires a form field followed by a list of attributes and values in the form attr="value"' % token.split_contents()[0]
      try:
          bits = token.split_contents()
          tag_name = bits[0]
          form_field = bits[1]
          attr_list = bits[2:]
      except ValueError:
          raise TemplateSyntaxError(error_msg)
  
      form_field = parser.compile_filter(form_field)
  
      set_attrs = []
      append_attrs = []
      for pair in attr_list:
          match = ATTRIBUTE_RE.match(pair)
          if not match:
              raise TemplateSyntaxError(error_msg + ": %s" % pair)
          dct = match.groupdict()
          attr, sign, value = \
              dct['attr'], dct['sign'], parser.compile_filter(dct['value'])
          if sign == "=":
              set_attrs.append((attr, value))
          else:
              append_attrs.append((attr, value))
  
      return FieldAttributeNode(form_field, set_attrs, append_attrs)
docs: Render a form field using given attribute-value pairs
  
      Takes form field as first argument and list of attribute-value pairs for
      all other arguments.  Attribute-value pairs should be in the form of
      attribute=value or attribute="a value" for assignment and attribute+=value
      or attribute+="value" for appending.