Add some methods for the cell

[JosePizarro3]

I am going to add some methods to ModelSystem and/or Cell/AtomicCell to make our lives easier during parsing:

• from_ase(): right now we have to_ase, but we can define the "from" one.
• get_atom_symbols(): this one is to pass the AtomsState(chemical_symbol) information to a flat list (as it was originally in the schema).

@ndaelman-hu @EBB2675 please, feel free to suggest other methods that you think might be interesting as well

[ndaelman-hu]

okay, thx for the heads-up! maybe some ideas will come when reviewing the draft

get_atom_symbols(): this one is to pass the AtomsState(chemical_symbol) information to a flat list (as it was originally in the schema).

So you mean that the function returns list[str]?

[JosePizarro3]

okay, thx for the heads-up! maybe some ideas will come when reviewing the draft

get_atom_symbols(): this one is to pass the AtomsState(chemical_symbol) information to a flat list (as it was originally in the schema).

So you mean that the function returns list[str]?

yeah