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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 formation_energy(self, chemical_potentials=None, fermi_level=0):
 """ Computes the formation energy for a defect taking into account a given chemical potential and fermi_level """

        chemical_potentials = chemical_potentials if chemical_potentials else {}

        chempot_correction = sum([
            chem_pot * (self.bulk_structure.composition[el] - self.defect.defect_composition[el])
            for el, chem_pot in chemical_potentials.items()
        ])

        formation_energy = self.energy + chempot_correction

        if "vbm" in self.parameters:
            formation_energy += self.charge * (self.parameters["vbm"] + fermi_level)
        else:
            formation_energy += self.charge * fermi_level

        return formation_energy