old_contents: """Constants module."""
  
  import math as _math
  from . import base_units as _u
  
  
  # temporary auxiliary derived units
  _volt = (_u.kilogram * _u.meter**2) / (_u.ampere * _u.second**2)
  _coulomb = _u.second * _u.ampere
  _joule = _u.kilogram * _u.meter**2 / _u.second**2
  _pascal = _u.kilogram / (_u.meter * _u.second**2)
  
  
  # physical constants
  # ==================
  
  # --- exact --
  
  light_speed = 299792458 * (_u.meter/_u.second)
  
  gas_constant = 8.314462618 * (_joule / _u.mole / _u.kelvin)
  
  boltzmann_constant = 1.380649e-23 * (_joule / _u.kelvin)
  
  avogadro_constant = 6.02214076e23 * (1 / _u.mole)
  
  elementary_charge = 1.602176634e-19 * _coulomb
  
  reduced_planck_constant = 1.054571817e-34 * _joule * _u.second
  
  # --- measured ---
  
  # 2021-04-15 - https://physics.nist.gov/cgi-bin/cuu/Value?me|search_for=electron+mass
  electron_mass = 9.1093837015e-31 * _u.kilogram
  
  # 2021-04-15 - https://physics.nist.gov/cgi-bin/cuu/Value?mu0|search_for=vacuum+permeability
  vacuum_permeability = 1.25663706212e-6 * \
      (_volt * _u.second / _u.ampere / _u.meter)
  
  # --- derived ---
  
  # [Kg̣*m^2/s^2] - derived
  electron_rest_energy = electron_mass * _math.pow(light_speed, 2)
  
  # [V·s/(A.m)]  - derived
  vacuum_permitticity = 1.0/(vacuum_permeability * _math.pow(light_speed, 2))
  
  # [T·m^2/(A·s)] - derived
  vacuum_impedance = vacuum_permeability * light_speed
  
  # [m] - derived
  electron_radius = _math.pow(elementary_charge, 2) / \
      (4*_math.pi*vacuum_permitticity*electron_rest_energy)
  
  _joule_2_eV = _joule / elementary_charge
  
  # [m]/[GeV]^3 - derived
  rad_cgamma = 4*_math.pi*electron_radius / \
      _math.pow(electron_rest_energy/elementary_charge/1.0e9, 3) / 3
  
  # [m] - derived
  Cq = (55.0/(32*_math.sqrt(3.0))) * (reduced_planck_constant) * \
      light_speed / electron_rest_energy
  
  # [m^2/(s·GeV^3)] - derived
  Ca = electron_radius*light_speed / \
      (3*_math.pow(electron_rest_energy*_joule_2_eV/1.0e9, 3))
  
new_contents: """Constants module."""
  
  import math as _math
  from . import base_units as _u
  
  
  # temporary auxiliary derived units
  _volt = (_u.kilogram * _u.meter**2) / (_u.ampere * _u.second**2)
  _coulomb = _u.second * _u.ampere
  _joule = _u.kilogram * _u.meter**2 / _u.second**2
  _pascal = _u.kilogram / (_u.meter * _u.second**2)
  
  
  # physical constants
  # ==================
  
  # --- exact --
  
  light_speed = 299792458 * (_u.meter/_u.second)
  
  gas_constant = 8.314462618 * (_joule / _u.mole / _u.kelvin)
  
  boltzmann_constant = 1.380649e-23 * (_joule / _u.kelvin)
  
  avogadro_constant = 6.02214076e23 * (1 / _u.mole)
  
  elementary_charge = 1.602176634e-19 * (_coulomb)
  
  reduced_planck_constant = 1.054571817e-34 * (_joule * _u.second)
  
  # --- measured ---
  
  # 2021-04-15 - https://physics.nist.gov/cgi-bin/cuu/Value?me|search_for=electron+mass
  electron_mass = 9.1093837015e-31 * (_u.kilogram)
  
  # 2021-04-15 - https://physics.nist.gov/cgi-bin/cuu/Value?mu0|search_for=vacuum+permeability
  vacuum_permeability = 1.25663706212e-6 * \
      (_volt * _u.second / _u.ampere / _u.meter)
  
  # --- derived ---
  
  # [Kg̣*m^2/s^2] - derived
  electron_rest_energy = electron_mass * _math.pow(light_speed, 2)
  
  # [V·s/(A.m)]  - derived
  vacuum_permitticity = 1.0/(vacuum_permeability * _math.pow(light_speed, 2))
  
  # [T·m^2/(A·s)] - derived
  vacuum_impedance = vacuum_permeability * light_speed
  
  # [m] - derived
  electron_radius = _math.pow(elementary_charge, 2) / \
      (4*_math.pi*vacuum_permitticity*electron_rest_energy)
  
  _joule_2_eV = _joule / elementary_charge
  
  # [m]/[GeV]^3 - derived
  rad_cgamma = 4*_math.pi*electron_radius / \
      _math.pow(electron_rest_energy/elementary_charge/1.0e9, 3) / 3
  
  # [m] - derived
  Cq = (55.0/(32*_math.sqrt(3.0))) * (reduced_planck_constant) * \
      light_speed / electron_rest_energy
  
  # [m^2/(s·GeV^3)] - derived
  Ca = electron_radius*light_speed / \
      (3*_math.pow(electron_rest_energy*_joule_2_eV/1.0e9, 3))
  
subject: Update consts formatting