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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 automatic_density_by_vol(structure, kppvol, force_gamma=False):
 """ Returns an automatic Kpoint object based on a structure and a kpoint density per inverse Angstrom^3 of reciprocal cell. Algorithm: Same as automatic_density() Args: structure (Structure):
 Input structure kppvol (int):
 Grid density per Angstrom^(-3) of reciprocal cell force_gamma (bool):
 Force a gamma centered mesh Returns: Kpoints """

        vol = structure.lattice.reciprocal_lattice.volume
        kppa = kppvol * vol * structure.num_sites
        return Kpoints.automatic_density(structure, kppa,
                                         force_gamma=force_gamma)