@remove_hairs_decorator<EOL><INDENT>def get_part_name(self, undefined="<STR_LIT>"):<DEDENT>
return _undefined_pattern(<EOL>"<STR_LIT>".join(self.get_subfields("<STR_LIT>", "<STR_LIT:n>")),<EOL>lambda x: x.strip() == "<STR_LIT>",<EOL>undefined<EOL>)<EOL>
Args:
    undefined (optional): Argument, which will be returned if the
              `part_name` record is not found.

Returns:
    str: Name of the part of the series. or `undefined` if `part_name`\
         is not found.