import CoolProp
masses = {'Cl': 35.45, 'H':1.008,'C':12.011,'O':15.999,'N':14.007,'Ar':39.948,'S':32.06,'Si':28.085,'F':18.998,'D':2.01410,'He':4.0026,'Kr':83.798,'Ne':20.180,'I':126.90,'Xe':131.29}
for fluid in CoolProp.__fluids__:
    formula = CoolProp.CoolProp.get_fluid_param_string(fluid, "formula")
    if formula == 'N/A': continue
    bits = [_ for _ in formula.split('}') if _]
    m = 0
    for b in bits:
        el, c = b.replace('_','').split('{')
        m += masses[el]*int(c)/1000.0
    err = m/CoolProp.CoolProp.PropsSI(fluid,"M")-1
    if abs(err) > 1e-3:
        print(fluid, m/CoolProp.CoolProp.PropsSI(fluid,"M")-1)