code: def _GetFieldPathElementIndex(api_error, field):
    
    field_path_elements = api_error['fieldPathElements']
  
    if field_path_elements:
      found_index = [field_path_element['index']
                     for field_path_element in field_path_elements
                     if field_path_element['field'] == field]
      if found_index:
        return found_index
  
    return None
docs: Retrieve the index of a given field in the api_error's fieldPathElements.
  
    Args:
      api_error: a dict containing a partialFailureError returned from the AdWords
        API.
      field: a str field for which this determines the index in the api_error's
        fieldPathElements.
  
    Returns:
      An int index of the field path element, or None if the specified field can't
      be found in the api_error.