code: def slide(self, distance):
          
          distance = float(distance)
          translation = np.eye(4)
          translation[2, 3] = distance
          new_transform = np.dot(self.primitive.transform.copy(),
                                 translation.copy())
          self.primitive.transform = new_transform
docs: Alter the transform of the current extrusion to slide it
          along its extrude_direction vector
  
          Parameters
          -----------
          distance: float, distance along self.extrude_direction to move