def control_number(endpoint):
def _control_number(self, key, value):<EOL><INDENT>self['<STR_LIT>'] = get_record_ref(int(value), endpoint)<EOL>return int(value)<EOL><DEDENT>return _control_number<EOL>
Populate the ``control_number`` key.

    Also populates the ``self`` key through side effects.