docs: def run(cls, row, reader):
          """ Invoke the CSV parser on an individual row
  
          The row should already be a dict from the CSV reader.
          The reader is passed in so we can easily reference the
          CSV document headers & line number when generating
          errors.
          """
  
          cls._parse_keys(row, reader.line_num)
          cls._parse_relationships(row, reader.line_num)