def _doNotMatch(inv, atoms):
  """ Helper function to check if all atoms in the list are NOT the same
      
      Arguments:
      - inv:    atom invariants (used to define equivalence of atoms)
      - atoms:  list of atoms to check

      Return: boolean
  """
  match = True
  for i in range(len(atoms)-1):
    for j in range(i+1, len(atoms)):
      if (inv[atoms[i].GetIdx()] == inv[atoms[j].GetIdx()]):
        match = False
        return match
  return match