code: def spawn(self, channels, ax):
          
          if _check_spawnable(self.source_channels, channels):
              sgate = self.gate_type(self.verts, ax, channels)
              self.spawn_list.append(sgate)
              return sgate
          else:
              return None
docs: Spawns a graphical gate that can be used to update the coordinates of the current gate.