def StielPolar(Tc=None, Pc=None, omega=None, CASRN='<STR_LIT>', Method=None,<EOL>AvailableMethods=False):
def list_methods():<EOL><INDENT>methods = []<EOL>if Tc and Pc and omega:<EOL><INDENT>methods.append('<STR_LIT>')<EOL><DEDENT>methods.append('<STR_LIT>')<EOL>return methods<EOL><DEDENT>if AvailableMethods:<EOL><INDENT>return list_methods()<EOL><DEDENT>if not Method:<EOL><INDENT>Method = list_methods()[<NUM_LIT:0>]<EOL><DEDENT>if Method == '<STR_LIT>':<EOL><INDENT>P = VaporPressure(CASRN=CASRN).T_dependent_property(Tc*<NUM_LIT>)<EOL>if not P:<EOL><INDENT>factor = None<EOL><DEDENT>else:<EOL><INDENT>Pr = P/Pc<EOL>factor = log10(Pr) + <NUM_LIT>*omega + <NUM_LIT><EOL><DEDENT><DEDENT>elif Method == '<STR_LIT>':<EOL><INDENT>factor = None<EOL><DEDENT>else:<EOL><INDENT>raise Exception('<STR_LIT>')<EOL><DEDENT>return factor<EOL>
r'''This function handles the calculation of a chemical's Stiel Polar
    factor, directly through the definition of Stiel-polar factor if possible.
    Requires Tc, Pc, acentric factor, and a vapor pressure datum at Tr=0.6.

    Will automatically select a method to use if no Method is provided;
    returns None if the data is not available and cannot be calculated.

    .. math::
        x = \log P_r|_{T_r=0.6} + 1.70 \omega + 1.552

    Parameters
    ----------
    Tc : float
        Critical temperature of fluid [K]
    Pc : float
        Critical pressure of fluid [Pa]
    omega : float
        Acentric factor of the fluid [-]
    CASRN : string
        CASRN [-]

    Returns
    -------
    factor : float
        Stiel polar factor of compound
    methods : list, only returned if AvailableMethods == True
        List of methods which can be used to obtain Stiel polar factor with the
        given inputs

    Other Parameters
    ----------------
    Method : string, optional
        The method name to use. Only 'DEFINITION' is accepted so far.
        All valid values are also held in the list Stiel_polar_methods.
    AvailableMethods : bool, optional
        If True, function will determine which methods can be used to obtain
        Stiel-polar factor for the desired chemical, and will return methods
        instead of stiel-polar factor

    Notes
    -----
    Only one source is available for this function. It is:

        * 'DEFINITION', based on the definition of
          Stiel Polar Factor presented in [1]_, using vapor pressure data.

    A few points have also been published in [2]_, which may be used for
    comparison. Currently this is only used for a surface tension correlation.

    Examples
    --------
    >>> StielPolar(647.3, 22048321.0, 0.344, CASRN='7732-18-5')
    0.024581140348734376

    References
    ----------
    .. [1] Halm, Roland L., and Leonard I. Stiel. "A Fourth Parameter for the
       Vapor Pressure and Entropy of Vaporization of Polar Fluids." AIChE
       Journal 13, no. 2 (1967): 351-355. doi:10.1002/aic.690130228.
    .. [2] D, Kukoljac Miloš, and Grozdanić Dušan K. "New Values of the
       Polarity Factor." Journal of the Serbian Chemical Society 65, no. 12
       (January 1, 2000). http://www.shd.org.rs/JSCS/Vol65/No12-Pdf/JSCS12-07.pdf