Class scope vs module scope attributes in Python -

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i declare class computations using several hard-coded constants defined class attributes. of methods similar following:

class iapws_1995:     @staticmethod     def dar_ddelta(delta, tau, delta, theta, psi):         _dar_ddelta = \             sum(iapws_1995.n_0 * iapws_1995.d_0 * pow(delta, iapws_1995.d_0-1) * pow(tau, iapws_1995.t_0)) + \             sum(iapws_1995.n_1 * exp(-pow(delta, iapws_1995.c_1)) * (pow(delta, iapws_1995.d_1-1) * pow(tau, iapws_1995.t_1) * (iapws_1995.d_1 - iapws_1995.c_1*pow(delta, iapws_1995.c_1)))) + \             sum(iapws_1995.n_2 * pow(delta, iapws_1995.d_2)*pow(tau, iapws_1995.t_2) * exp(-iapws_1995.alpha_2*(delta-iapws_1995.epsilon_2)**2 - iapws_1995.beta_2*(tau-iapws_1995.gamma_2)**2) * (iapws_1995.d_2/delta - 2*iapws_1995.alpha_2*(delta-iapws_1995.epsilon_2))) + \             sum(iapws_1995.n_3 * (pow(delta, iapws_1995.b_3)*(psi + delta*iapws_1995.dpsi_ddelta(psi, delta)) + iapws_1995.ddeltab_ddelta(delta, delta, theta)*delta*psi))         return _dar_ddelta

the class scope qualifiers makes code (even more) difficult read. had thought of doing make code more readable:

... _ = iapws_1995 _dar_ddelta = \     sum(_.n_0 * _.d_0 * pow(delta, _.d_0-1) * pow(tau, _.t_0)) + \ ...

if move constant declarations module scope, though, don't need scope qualifiers @ all.

is there reason prefer declaring constants in class on module (e.g. namespace collisions if have similar class iapws_2014 in future?)

another approach create module called iapws_1995, since aren't instantiating objects class. module like:

n_0, n_1, n_2, n_3 = ... d_0, d_1, d_2 = ... t_0, t_1, t_2 = ... c_1, = ... b_3, = ... alpha_2, beta_2, gamma_2, epsilon_2 = ... dpsi_ddelta = ... ddeltab_ddelta = ...  def dar_ddelta(delta, tau, delta, theta, psi):     _dar_ddelta = (         sum(n_0 * d_0 * pow(delta, d_0-1) * pow(tau, t_0)) +         sum(n_1 * exp(-pow(delta, c_1)) * (pow(delta, d_1-1) * pow(tau, t_1) * (d_1 - c_1*pow(delta, c_1)))) +         sum(n_2 * pow(delta, d_2)*pow(tau, t_2) * exp(-alpha_2*(delta-epsilon_2)**2 - beta_2*(tau-gamma_2)**2) * (d_2/delta - 2*alpha_2*(delta-epsilon_2))) + \         sum(n_3 * (pow(delta, b_3)*(psi + delta*dpsi_ddelta(psi, delta)) + ddeltab_ddelta(delta, delta, theta)*delta*psi)))         return _dar_ddelta

with constants module-level variables, , class method module-level function.

other code use this:

import iapw2_1995  x = iapw2_1995.dar_ddelta( arg1, arg2, arg3, arg4, arg5 )

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