code: def rotate(self, theta, around):
          
          new_positions = _rotate(self.xyz_with_ports, theta, around)
          self.xyz_with_ports = new_positions
docs: Rotate Compound around an arbitrary vector.
  
          Parameters
          ----------
          theta : float
              The angle by which to rotate the Compound, in radians.
          around : np.ndarray, shape=(3,), dtype=float
              The vector about which to rotate the Compound.