docs: def get_atom_map(structure):
      """
      Returns a dict that maps each atomic symbol to a unique integer starting
      from 1.
  
      Args:
          structure (Structure)
  
      Returns:
          dict
      """
      syms = [site.specie.symbol for site in structure]
      unique_pot_atoms = []
      [unique_pot_atoms.append(i) for i in syms if not unique_pot_atoms.count(i)]
      atom_map = {}
      for i, atom in enumerate(unique_pot_atoms):
          atom_map[atom] = i + 1
      return atom_map