How to use the pythoms.molecule.Molecule function in pythoms

def setUp(self):
        self.mol = Molecule('L2PdAr+I')
        self.ipmol = IPMolecule(
            'L2PdAr+I',
            ipmethod='multiplicative',
            dropmethod='threshold',
            threshold=0.01,
        )

def __iadd__(self, other):
        if type(other) is str:
            other = composition_from_formula(other)
        elif isinstance(other, Molecule) is True:
            other = other.composition
        elif type(other) == dict:
            pass
        else:
            raise ValueError(f'Addition of {other} to {self} is invalid')
        new = copy.copy(self._comp)  # starter for new dictionary
        for key in other:
            try:
                new[key] += other[key]
            except KeyError:
                new[key] = other[key]
        self.composition = new
        return self

sys.stdout.write(f'{self}\n')
        sys.stdout.write(f'formula: {self.molecular_formula}\n')
        sys.stdout.write(f'molecular weight: {round(self.molecular_weight, 6)}\n')
        sys.stdout.write(f'monoisotopic mass: {round(self.monoisotopic_mass, 6)}\n')
        sys.stdout.write('\n')
        self.print_percent_composition()

    def print_percent_composition(self):
        """prints the percent composition in a reader-friendly format"""
        sys.stdout.write('elemental percent composition:\n')
        pcomp = self.percent_composition
        for element, percent in sorted(pcomp.items()):
            sys.stdout.write(f'{element}: {percent * 100.:6.4}%\n')


class IPMolecule(Molecule):
    _ipmethod = None
    _gausip = None  # gaussian isotope pattern storage
    _dropmethod = None

    def __init__(self,
                 string: (str, dict),
                 charge=1,
                 consolidate=3,
                 criticalerror=3 * 10 ** -6,
                 decpl=7,
                 dropmethod=None,
                 emptyspec=True,
                 groupmethod='weighted',
                 ipmethod='hybrid',
                 keepall=False,
                 npeaks=5000,