code: def signed_hms(self, warn=True):
          
          if warn and self.preference != 'hours':
              raise WrongUnitError('signed_hms')
          return _sexagesimalize_to_float(self._hours)
docs: Convert to a tuple (sign, hours, minutes, seconds).
  
          The ``sign`` will be either +1 or -1, and the other quantities
          will all be positive.