code: def insert_extracted_value(self, doc, extracted_value,
                                 output_field, original_output_field=None):
          
          if not extracted_value:
              return doc
          metadata = self.extractor.get_metadata()
          if not self.extractor.get_include_context():
              if isinstance(extracted_value, list):
                  result = list()
                  for ev in extracted_value:
                      result.append({'value': ev})
              else:
                  result = {'value': extracted_value}
          else:
              result = extracted_value
          metadata['result'] = result
          metadata['source'] = str(self.input_fields)
  
          if original_output_field is not None:
              metadata['original_output_field'] = original_output_field
  
          if self.name is not None:
              metadata['name'] = self.name
  
          field_elements = output_field.split('.')
          while len(field_elements) > 1:
              field_element = field_elements.pop(0)
              if '[' in field_element:
                  if not field_element.startswith('['):
                      array_field_elements = field_element.split('[', 1)
                      array_field_element = array_field_elements[0]
                      doc = doc[array_field_element]
                      field_element = array_field_elements[1]
                  array_elements = field_element.split(']')
                  for array_element in array_elements:
                      if not array_element:
                          continue
                      if array_element.startswith('['):
                          array_element = array_element[1:]
                      if array_element.isdigit() and isinstance(doc, list):
                          doc = doc[int(array_element)]
                      else:
                          doc = doc[array_element]
              else:
                  if field_element not in doc:
                      doc[field_element] = {}
                  doc = doc[field_element]
          field_element = field_elements[0]
          if field_element in doc:
              output = doc[field_element]
              if isinstance(output, dict):
                  output = [output, metadata]
              elif isinstance(output, types.ListType):
                  output.append(metadata)
  
          else:
              output = [metadata]
          doc[field_element] = output
docs: inserts the extracted value into doc at the field specified 
          by output_field