code: def iter_channels(self, skip_master=True, copy_master=True):
          
  
          for i, group in enumerate(self.groups):
  
              included_channels = self._included_channels(i, skip_master=skip_master)
  
              channels = [
                  (None, i, idx)
                  for idx in included_channels
              ]
  
              channels = self.select(
                  channels,
                  copy_master=copy_master,
              )
  
              for channel in channels:
                  yield channel
docs: generator that yields a *Signal* for each non-master channel
  
          Parameters
          ----------
          skip_master : bool
              do not yield master channels; default *True*
          copy_master : bool
              copy master for each yielded channel