Prandtl number cannot be returned directly

[ibell]

In [1]: import CoolProp

In [2]: CoolProp.CoolProp.PropsSI('Prandtl','T',300,'P',101325,'Nitrogen')
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-2-19907aefdc78> in <module>()
----> 1 CoolProp.CoolProp.PropsSI('Prandtl','T',300,'P',101325,'Nitrogen')

C:\Miniconda\lib\site-packages\coolprop-5.0.7dev-py2.7-win-amd64.egg\CoolProp\CoolProp.pyd in CoolProp.CoolProp.PropsSI (CoolProp\CoolProp.cpp:16127)()

C:\Miniconda\lib\site-packages\coolprop-5.0.7dev-py2.7-win-amd64.egg\CoolProp\CoolProp.pyd in CoolProp.CoolProp.PropsSI (CoolProp\CoolProp.cpp:15930)()

C:\Miniconda\lib\site-packages\coolprop-5.0.7dev-py2.7-win-amd64.egg\CoolProp\CoolProp.pyd in CoolProp.CoolProp.__Props_err2 (CoolProp\CoolProp.cpp:14348)()

ValueError: This input [42: "Prandtl"] is not valid for keyed_output : PropsSI("Prandtl","T",300,"P",101325,"Nitrogen")