How to use the quantities.unitquantity.UnitConstant function in quantities

)
atomic_mass_unit_inverse_meter_relationship = UnitConstant(
    'atomic_mass_unit_inverse_meter_relationship',
    _cd('atomic mass unit-inverse meter relationship')
)
atomic_mass_unit_joule_relationship = UnitConstant(
    'atomic_mass_unit_joule_relationship',
    _cd('atomic mass unit-joule relationship'),
    symbol='(u*c**2)',
    u_symbol='(u·c²)'
)
atomic_mass_unit_kelvin_relationship = UnitConstant(
    'atomic_mass_unit_kelvin_relationship',
    _cd('atomic mass unit-kelvin relationship')
)
atomic_mass_unit_kilogram_relationship = UnitConstant(
    'atomic_mass_unit_kilogram_relationship',
    _cd('atomic mass unit-kilogram relationship')
)

hartree_atomic_mass_unit_relationship = UnitConstant(
    'hartree_atomic_mass_unit_relationship',
    _cd('hartree-atomic mass unit relationship')
)
hartree_electron_volt_relationship = UnitConstant(
    'hartree_electron_volt_relationship',
    _cd('hartree-electron volt relationship')
)
hartree_hertz_relationship = UnitConstant(
    'hartree_hertz_relationship',
    _cd('hartree-hertz relationship')
)

)
alpha_particle_mass_energy_equivalent = UnitConstant(
    'alpha_particle_mass_energy_equivalent',
    _cd('alpha particle mass energy equivalent'),
    symbol='(m_alpha*c**2)',
    u_symbol='(m_α·c²)'
)
alpha_particle_mass_energy_equivalent_in_MeV = UnitConstant(
    'alpha_particle_mass_energy_equivalent_in_MeV',
    _cd('alpha particle mass energy equivalent in MeV'),
)
alpha_particle_mass_in_u = UnitConstant(
    'alpha_particle_mass_in_u',
    _cd('alpha particle mass in u')
)
alpha_particle_molar_mass = UnitConstant(
    'alpha_particle_molar_mass',
    _cd('alpha particle molar mass'),
    symbol='M_alpha',
    u_symbol='M_α'
)
alpha_particle_electron_mass_ratio = UnitConstant(
    'alpha_particle_electron_mass_ratio',
    _cd('alpha particle-electron mass ratio'),
    symbol='(m_alpha/m_e)',
    u_symbol='(m_α/mₑ)'
)
alpha_particle_proton_mass_ratio = UnitConstant(
    'alpha_particle_proton_mass_ratio',
    _cd('alpha particle-proton mass ratio'),
    symbol='(m_alpha/m_p)',
    u_symbol='(m_α/m_p)'

symbol='(mu_p/mu_N)',
    u_symbol='(μ_p/μ_N)'
)
proton_neutron_magnetic_moment_ratio = UnitConstant(
    'proton_neutron_magnetic_moment_ratio',
    _cd('proton-neutron magnetic moment ratio'),
    symbol='(mu_p/mu_n)',
    u_symbol='(μ_p/μ_n)'
)
shielded_proton_magnetic_moment_to_Bohr_magneton_ratio = UnitConstant(
    'shielded_proton_magnetic_moment_to_Bohr_magneton_ratio',
    _cd('shielded proton magnetic moment to Bohr magneton ratio'),
    symbol='(muprime_p/mu_B)',
    u_symbol='(μ′_p/μ_B)'
)
shielded_proton_magnetic_moment_to_nuclear_magneton_ratio = UnitConstant(
    'shielded_proton_magnetic_moment_to_nuclear_magneton_ratio',
    _cd('shielded proton magnetic moment to nuclear magneton ratio'),
    symbol='(muprime_p/mu_N)',
    u_symbol='(μ′_p/μ_N)'
)

del UnitConstant, _cd

)
helion_mass_energy_equivalent = UnitConstant(
    'helion_mass_energy_equivalent',
    _cd('helion mass energy equivalent'),
    symbol='(m_h*c**2)',
    u_symbol='(m_h·c²)'
)
helion_mass_energy_equivalent_in_MeV = UnitConstant(
    'helion_mass_energy_equivalent_in_MeV',
    _cd('helion mass energy equivalent in MeV')
)
helion_mass_in_u = UnitConstant(
    'helion_mass_in_u',
    _cd('helion mass in u')
)
helion_molar_mass = UnitConstant(
    'helion_molar_mass',
    _cd('helion molar mass'),
    symbol='M_h'
)
helion_electron_mass_ratio = UnitConstant(
    'helion_electron_mass_ratio',
    _cd('helion-electron mass ratio'),
    symbol='(m_h/m_e)',
    u_symbol='(m_h/mₑ)'
)
helion_proton_mass_ratio = UnitConstant(
    'helion_proton_mass_ratio',
    _cd('helion-proton mass ratio'),
    symbol='(m_h/m_p)'
)

'kelvin_inverse_meter_relationship',
    _cd('kelvin-inverse meter relationship')
)
kelvin_joule_relationship = UnitConstant(
    'kelvin_joule_relationship',
    _cd('kelvin-joule relationship')
)
kelvin_kilogram_relationship = UnitConstant(
    'kelvin_kilogram_relationship',
    _cd('kelvin-kilogram relationship')
)
kilogram_hertz_relationship = UnitConstant(
    'kilogram_hertz_relationship',
    _cd('kilogram-hertz relationship')
)
kilogram_inverse_meter_relationship = UnitConstant(
    'kilogram_inverse_meter_relationship',
    _cd('kilogram-inverse meter relationship')
)
kilogram_joule_relationship = UnitConstant(
    'kilogram_joule_relationship',
    _cd('kilogram-joule relationship')
)
kilogram_kelvin_relationship = UnitConstant(
    'kilogram_kelvin_relationship',
    _cd('kilogram-kelvin relationship')
)

del UnitConstant, _cd

_cd('electron mass in u')
)
electron_molar_mass = UnitConstant(
    'electron_molar_mass',
    _cd('electron molar mass'),
    symbol='M_e',
    u_symbol='Mₑ'
)

electron_deuteron_mass_ratio = UnitConstant(
    'electron_deuteron_mass_ratio',
    _cd('electron-deuteron mass ratio'),
    symbol='(m_e/m_d)',
    u_symbol='(mₑ/m_d)'
)
electron_muon_mass_ratio = UnitConstant(
    'electron_muon_mass_ratio',
    _cd('electron-muon mass ratio'),
    symbol='(m_e/m_mu)',
    u_symbol='(mₑ/m_μ)'
)
electron_neutron_mass_ratio = UnitConstant(
    'electron_neutron_mass_ratio',
    _cd('electron-neutron mass ratio'),
    symbol='(m_e/m_n)',
    u_symbol='(mₑ/m_n)'
)
electron_proton_mass_ratio = UnitConstant(
    'electron_proton_mass_ratio',
    _cd('electron-proton mass ratio'),
    symbol='(m_e/m_p)',
    u_symbol='(mₑ/m_p)'

symbol='(hbar/a_0)',
    u_symbol='(ħ/a₀)'
)
atomic_unit_of_permittivity = UnitConstant(
    'atomic_unit_of_permittivity',
    _cd('atomic unit of permittivity'),
    symbol='(e**2/(a_0*E_h))',
    u_symbol='(e²/(a₀·E_h))'
)
atomic_unit_of_time = UnitConstant(
    'atomic_unit_of_time',
    _cd('atomic unit of time'),
    symbol='(hbar/E_h)',
    u_symbol='(ħ/E_h)'
)
atomic_unit_of_velocity = UnitConstant(
    'atomic_unit_of_velocity',
    _cd('atomic unit of velocity'),
    symbol='(a_0*E_h/hbar)',
    u_symbol='(a₀·E_h/ħ)'
)
N_A = L = Avogadro_constant = UnitConstant(
    'Avogadro_constant',
    _cd('Avogadro constant'),
    symbol='N_A'
)
mu_B = Bohr_magneton = UnitConstant(
    'Bohr_magneton',
    _cd('Bohr magneton'),
    symbol='mu_B',
    u_symbol='μ_B'
)

Boltzmann_constant_in_inverse_meters_per_kelvin = UnitConstant(
    'Boltzmann_constant_in_inverse_meters_per_kelvin',
    _cd('Boltzmann constant in inverse meters per kelvin')
)

M_u = molar_mass_constant = UnitConstant(
    'molar_mass_constant',
    _cd('molar mass constant'),
    symbol='M_u',
    u_symbol='Mᵤ'
)
molar_volume_of_ideal_gas_ST_100kPa = UnitConstant(
    'molar_volume_of_ideal_gas_ST_100kPa',
    _cd('molar volume of ideal gas (273.15 K, 100 kPa)')
)
molar_volume_of_ideal_gas_STP = UnitConstant(
    'molar_volume_of_ideal_gas_STP',
    _cd('molar volume of ideal gas (273.15 K, 101.325 kPa)')
)
molar_volume_of_silicon = UnitConstant(
    'molar_volume_of_silicon',
    _cd('molar volume of silicon')
)

del UnitConstant, _cd

electron_mass_energy_equivalent = UnitConstant(
    'electron_mass_energy_equivalent',
    _cd('electron mass energy equivalent'),
    symbol='(m_e*c**2)',
    u_symbol='(mₑ·c²)'
)
electron_mass_energy_equivalent_in_MeV = UnitConstant(
    'electron_mass_energy_equivalent_in_MeV',
    _cd('electron mass energy equivalent in MeV')
)
electron_mass_in_u = UnitConstant(
    'electron_mass_in_u',
    _cd('electron mass in u')
)
electron_molar_mass = UnitConstant(
    'electron_molar_mass',
    _cd('electron molar mass'),
    symbol='M_e',
    u_symbol='Mₑ'
)

electron_deuteron_mass_ratio = UnitConstant(
    'electron_deuteron_mass_ratio',
    _cd('electron-deuteron mass ratio'),
    symbol='(m_e/m_d)',
    u_symbol='(mₑ/m_d)'
)
electron_muon_mass_ratio = UnitConstant(
    'electron_muon_mass_ratio',
    _cd('electron-muon mass ratio'),
    symbol='(m_e/m_mu)',

'Compton_wavelength_over_2_pi',
    _cd('Compton wavelength over 2 pi'),
    symbol='lambdabar_C',
    u_symbol='ƛ_C'
)
G_0 = conductance_quantum = UnitConstant(
    'conductance_quantum',
    _cd('conductance quantum'),
    symbol='G_0',
    u_symbol='G₀'
)
K_J90 = conventional_value_of_Josephson_constant = UnitConstant(
    'conventional_value_of_Josephson_constant',
    _cd('conventional value of Josephson constant')
)
R_K90 = conventional_value_of_von_Klitzing_constant = UnitConstant(
    'conventional_value_of_von_Klitzing_constant',
    _cd('conventional value of von Klitzing constant')
)
Cu_x_unit = UnitConstant(
    'Cu_x_unit',
    _cd('Cu x unit'),
    symbol='CuKalpha_1',
    u_symbol='CuKα₁'
)
g_d = deuteron_g_factor = UnitConstant(
    'deuteron_g_factor',
    _cd('deuteron g factor'),
    symbol='g_d'
)
mu_d = deuteron_magnetic_moment = UnitConstant(
    'deuteron_magnetic_moment',