code: def get_energies(atoms_list):
      
      if len(atoms_list) == 1:
          return atoms_list[0].get_potential_energy()
      elif len(atoms_list) > 1:
          energies = []
          for atoms in atoms_list:
              energies.append(atoms.get_potential_energy())
          return energies
docs: Potential energy for a list of atoms objects