<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _get_id(self):
 """Construct and return the identifier"""

        return ''.join(map(str,
                           filter(is_not_None,
                                  [self.Prefix, self.Name])))