<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _update_atomtypes(unatomtyped_topology, res_name, prototype):
 """Update atomtypes in residues in a topology using a prototype topology. Atomtypes are updated when residues in each topology have matching names. Parameters unatomtyped_topology : openmm.app.Topology Topology lacking atomtypes defined by `find_atomtypes`. prototype : openmm.app.Topology Prototype topology with atomtypes defined by `find_atomtypes`. """

    for res in unatomtyped_topology.residues():
        if res.name == res_name:
            for old_atom, new_atom_id in zip([atom for atom in res.atoms()], [atom.id for atom in prototype.atoms()]):
                old_atom.id = new_atom_id