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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def standard(target, mol_weight='pore.molecular_weight', molar_density='pore.molar_density'):
 r""" Calculates the mass density from the molecular weight and molar density Parameters mol_weight : string The dictionary key containing the molecular weight values molar_density : string The dictionary key containing the molar density values """

    MW = target[mol_weight]
    rho = target[molar_density]
    value = rho*MW
    return value