code: def is_ambiguous(self, dt, idx=None):
          
          if idx is None:
              idx = self._find_last_transition(dt)
  
          # Calculate the difference in offsets from current to previous
          timestamp = _datetime_to_timestamp(dt)
          tti = self._get_ttinfo(idx)
  
          if idx is None or idx <= 0:
              return False
  
          od = self._get_ttinfo(idx - 1).offset - tti.offset
          tt = self._trans_list[idx]          # Transition time
  
          return timestamp < tt + od
docs: Whether or not the "wall time" of a given datetime is ambiguous in this
          zone.
  
          :param dt:
              A :py:class:`datetime.datetime`, naive or time zone aware.
  
  
          :return:
              Returns ``True`` if ambiguous, ``False`` otherwise.
  
          .. versionadded:: 2.6.0