code: def xyz(self, arrnx3):
          
          if not self.children:
              if not arrnx3.shape[0] == 1:
                  raise ValueError(
                      'Trying to set position of {} with more than one'
                      'coordinate: {}'.format(
                          self, arrnx3))
              self.pos = np.squeeze(arrnx3)
          else:
              for atom, coords in zip(
                  self._particles(
                      include_ports=False), arrnx3):
                  atom.pos = coords
docs: Set the positions of the particles in the Compound, excluding the Ports.
  
          This function does not set the position of the ports.
  
          Parameters
          ----------
          arrnx3 : np.ndarray, shape=(n,3), dtype=float
              The new particle positions