code: def detector_voltage(self, channels=None):
          
          # Check default
          if channels is None:
              channels = self._channels
  
          # Get numerical indices of channels
          channels = self._name_to_index(channels)
  
          # Get detector type of the specified channels
          if hasattr(channels, '__iter__') \
                  and not isinstance(channels, six.string_types):
              return [self._detector_voltage[ch] for ch in channels]
          else:
              return self._detector_voltage[channels]
docs: Get the detector voltage used for the specified channel(s).
  
          The detector voltage for channel "n" is extracted from the $PnV
          parameter, if available.
  
          Parameters
          ----------
          channels : int, str, list of int, list of str
              Channel(s) for which to get the detector voltage. If None,
              return a list with the detector voltage of all channels, in the
              order of ``FCSData.channels``.
  
          Return
          ------
          float or list of float
              The detector voltage of the specified channel(s). If no
              information about the detector voltage is found for a channel,
              return None.