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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def save(self, filename, show_ports=False, forcefield_name=None, forcefield_files=None, forcefield_debug=False, box=None, overwrite=False, residues=None, references_file=None, combining_rule='lorentz', foyerkwargs={}, **kwargs):
 """Save the Compound to a file. Parameters filename : str Filesystem path in which to save the trajectory. The extension or prefix will be parsed and control the format. Supported extensions are: 'hoomdxml', 'gsd', 'gro', 'top', 'lammps', 'lmp' show_ports : bool, optional, default=False Save ports contained within the compound. forcefield_files : str, optional, default=None Apply a forcefield to the output file using a forcefield provided by the `foyer` package. forcefield_name : str, optional, default=None Apply a named forcefield to the output file using the `foyer` package, e.g. 'oplsaa'. Forcefields listed here: https://github.com/mosdef-hub/foyer/tree/master/foyer/forcefields forcefield_debug : bool, optional, default=False Choose level of verbosity when applying a forcefield through `foyer`. Specifically, when missing atom types in the forcefield xml file, determine if the warning is condensed or verbose. box : mb.Box, optional, default=self.boundingbox (with buffer) Box information to be written to the output file. If 'None', a bounding box is used with 0.25nm buffers at each face to avoid overlapping atoms. overwrite : bool, optional, default=False Overwrite if the filename already exists residues : str of list of str Labels of residues in the Compound. Residues are assigned by checking against Compound.name. references_file : str, optional, default=None Specify a filename to write references for the forcefield that is to be applied. References are written in BiBTeX format. combining_rule : str, optional, default='lorentz' Specify the combining rule for nonbonded interactions. Only relevant when the `foyer` package is used to apply a forcefield. Valid options are 'lorentz' and 'geometric', specifying Lorentz-Berthelot and geometric combining rules respectively. Other Parameters foyerkwargs : dict, optional Specify keyword arguments when applying the foyer Forcefield ref_distance : float, optional, default=1.0 Normalization factor used when saving to .gsd and .hoomdxml formats for converting distance values to reduced units. ref_energy : float, optional, default=1.0 Normalization factor used when saving to .gsd and .hoomdxml formats for converting energy values to reduced units. ref_mass : float, optional, default=1.0 Normalization factor used when saving to .gsd and .hoomdxml formats for converting mass values to reduced units. atom_style: str, default='full' Defines the style of atoms to be saved in a LAMMPS data file. The following atom styles are currently supported: 'full', 'atomic', 'charge', 'molecular' see http://lammps.sandia.gov/doc/atom_style.html for more information on atom styles. See Also -------- formats.gsdwrite.write_gsd : Write to GSD format formats.hoomdxml.write_hoomdxml : Write to Hoomd XML format formats.lammpsdata.write_lammpsdata : Write to LAMMPS data format """

        extension = os.path.splitext(filename)[-1]
        if extension == '.xyz':
            traj = self.to_trajectory(show_ports=show_ports)
            traj.save(filename)
            return

        # Savers supported by mbuild.formats
        savers = {'.hoomdxml': write_hoomdxml,
                  '.gsd': write_gsd,
                  '.lammps': write_lammpsdata,
                  '.lmp': write_lammpsdata}

        try:
            saver = savers[extension]
        except KeyError:
            saver = None

        if os.path.exists(filename) and not overwrite:
            raise IOError('{0} exists; not overwriting'.format(filename))

        structure = self.to_parmed(box=box, residues=residues,
                                   show_ports=show_ports)
        # Apply a force field with foyer if specified
        if forcefield_name or forcefield_files:
            foyer = import_('foyer')
            ff = foyer.Forcefield(forcefield_files=forcefield_files,
                                  name=forcefield_name, debug=forcefield_debug)
            structure = ff.apply(structure, references_file=references_file,
                    **foyerkwargs)
            structure.combining_rule = combining_rule

        total_charge = sum([atom.charge for atom in structure])
        if round(total_charge, 4) != 0.0:
            warn('System is not charge neutral. Total charge is {}.'
                 ''.format(total_charge))

        # Provide a warning if rigid_ids are not sequential from 0
        if self.contains_rigid:
            unique_rigid_ids = sorted(set([
                p.rigid_id for p in self.rigid_particles()]))
            if max(unique_rigid_ids) != len(unique_rigid_ids) - 1:
                warn("Unique rigid body IDs are not sequential starting from zero.")

        if saver:  # mBuild supported saver.
            if extension in ['.gsd', '.hoomdxml']:
                kwargs['rigid_bodies'] = [
                        p.rigid_id for p in self.particles()]
            saver(filename=filename, structure=structure, **kwargs)
        else:  # ParmEd supported saver.
            structure.save(filename, overwrite=overwrite, **kwargs)