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

Returns:
    str: Information about order in which was the book published or \
         `undefined` if `pub_order` is not found.