@cache_readonly<EOL><INDENT>def month_roll(self):<DEDENT>
if self._prefix.endswith('<STR_LIT:S>'):<EOL><INDENT>roll_func = self.m_offset.rollback<EOL><DEDENT>else:<EOL><INDENT>roll_func = self.m_offset.rollforward<EOL><DEDENT>return roll_func<EOL>
Define default roll function to be called in apply method.