class Constants:
    # conversions from [unit] to a.u. equivalent
    atomic_units = {
        "wavenumbers": 4.55634e-6,
        "angstroms": 1 / 0.529177,
        "amu": 1.000000000000000000 / 6.02213670000e23 / 9.10938970000e-28
    }

    masses = {
        "H": (1.00782503223, "amu"),
        "O": (15.99491561957, "amu"),
        "D": (2.0141017778, "amu")
    }

    @classmethod
    def convert(cls, val, unit, to_AU=True):
        vv = cls.atomic_units[unit]
        return (val * vv) if to_AU else (val / vv)

    @classmethod
    def mass(cls, atom, to_AU=True):
        m = cls.masses[atom]
        if to_AU:
            m = cls.convert(*m)
        return m

3fbe0cbca2edbc64e665def1fcc6ec99cb22cb10
class Constants:
    <mask token>
    <mask token>
    <mask token>
    <mask token>

class Constants:
    <mask token>
    <mask token>
    <mask token>

    @classmethod
    def mass(cls, atom, to_AU=True):
        m = cls.masses[atom]
        if to_AU:
            m = cls.convert(*m)
        return m

class Constants:
    <mask token>
    <mask token>

    @classmethod
    def convert(cls, val, unit, to_AU=True):
        vv = cls.atomic_units[unit]
        return val * vv if to_AU else val / vv

    @classmethod
    def mass(cls, atom, to_AU=True):
        m = cls.masses[atom]
        if to_AU:
            m = cls.convert(*m)
        return m

class Constants:
    atomic_units = {'wavenumbers': 4.55634e-06, 'angstroms': 1 / 0.529177,
        'amu': 1.0 / 6.0221367e+23 / 9.1093897e-28}
    masses = {'H': (1.00782503223, 'amu'), 'O': (15.99491561957, 'amu'),
        'D': (2.0141017778, 'amu')}

    @classmethod
    def convert(cls, val, unit, to_AU=True):
        vv = cls.atomic_units[unit]
        return val * vv if to_AU else val / vv

    @classmethod
    def mass(cls, atom, to_AU=True):
        m = cls.masses[atom]
        if to_AU:
            m = cls.convert(*m)
        return m

class Constants:
    # conversions from [unit] to a.u. equivalent
    atomic_units = {
        "wavenumbers": 4.55634e-6,
        "angstroms": 1 / 0.529177,
        "amu": 1.000000000000000000 / 6.02213670000e23 / 9.10938970000e-28
    }

    masses = {
        "H": (1.00782503223, "amu"),
        "O": (15.99491561957, "amu"),
        "D": (2.0141017778, "amu")
    }

    @classmethod
    def convert(cls, val, unit, to_AU=True):
        vv = cls.atomic_units[unit]
        return (val * vv) if to_AU else (val / vv)

    @classmethod
    def mass(cls, atom, to_AU=True):
        m = cls.masses[atom]
        if to_AU:
            m = cls.convert(*m)
        return m
