code: def set_channel_names(self, names):
          
          if not names:
              self.chnames = None
              return
  
          if len(names) != len(self.keys):
              raise ValueError('len(names) != len(self.D.keys())')
  
          self.chnames = dict(zip(self.keys, names))
docs: Set self.chnames. Custom channel names that can be used in calls
          on this object and in condition strings.
  
          names: list or None
              It is the callers responsibility to make sure the list is in
              column order. self.chnames will be a dict with channel
              integer indexes as keys. If names is None, self.chnames will
              be None.