def Sheffy_Johnson(T, M, Tm):
return <NUM_LIT>*(<NUM_LIT:1> - <NUM_LIT>*(T - Tm))/(Tm**<NUM_LIT>*M**<NUM_LIT>)<EOL>
r'''Calculate the thermal conductivity of a liquid as a function of
    temperature using the Sheffy-Johnson (1961) method. Requires
    Temperature, molecular weight, and melting point.

    .. math::
        k = 1.951 \frac{1-0.00126(T-T_m)}{T_m^{0.216}MW^{0.3}}

    Parameters
    ----------
    T : float
        Temperature of the fluid [K]
    M : float
        Molecular weight of the fluid [g/mol]
    Tm : float
        Melting point of the fluid [K]

    Returns
    -------
    kl : float
        Thermal conductivity of the fluid, W/m/k

    Notes
    -----
    The origin of this equation has been challenging to trace. It is
    presently unknown, and untested.

    Examples
    --------
    >>> Sheffy_Johnson(300, 47, 280)
    0.17740150413112196

    References
    ----------
    .. [1] Scheffy, W. J., and E. F. Johnson. "Thermal Conductivities of
       Liquids at High Temperatures." Journal of Chemical & Engineering Data
       6, no. 2 (April 1, 1961): 245-49. doi:10.1021/je60010a019