<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def dmrs(self):
 """ Deserialize and return a Dmrs object for JSON-formatted DMRS data; otherwise return the original string. """

        dmrs = self.get('dmrs')
        if dmrs is not None:
            if isinstance(dmrs, dict):
                dmrs = Dmrs.from_dict(dmrs)
        return dmrs