code: def _from_datetime64(cls, data, freq, tz=None):
          
          data, freq = dt64arr_to_periodarr(data, freq, tz)
          return cls(data, freq=freq)
docs: Construct a PeriodArray from a datetime64 array
  
          Parameters
          ----------
          data : ndarray[datetime64[ns], datetime64[ns, tz]]
          freq : str or Tick
          tz : tzinfo, optional
  
          Returns
          -------
          PeriodArray[freq]