<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def set_trace(self, frame=None):
 """Remember starting frame. This is used with pytest, which does not use pdb.set_trace(). """

        if hasattr(local, '_pdbpp_completing'):
            # Handle set_trace being called during completion, e.g. with
            # fancycompleter's attr_matches.
            return
        if frame is None:
            frame = sys._getframe().f_back
        self._via_set_trace_frame = frame
        return super(Pdb, self).set_trace(frame)