code: def pos(self, p_x=None, y=None, z=None):
          
          if p_x is None:
              return np.array(self.GetPosition())
          if z is None:  # assume p_x is of the form (x,y,z)
              self.SetPosition(p_x)
          else:
              self.SetPosition(p_x, y, z)
          if self.trail:
              self.updateTrail()
          return self
docs: Set/Get actor position.