def Ambrose_Walton(T, Tc, Pc, omega):
Tr = T/Tc<EOL>tau = <NUM_LIT:1> - T/Tc<EOL>f0 = (-<NUM_LIT>*tau + <NUM_LIT>*tau**<NUM_LIT> - <NUM_LIT>*tau**<NUM_LIT> - <NUM_LIT>*tau**<NUM_LIT:5>)/Tr<EOL>f1 = (-<NUM_LIT>*tau + <NUM_LIT>*tau**<NUM_LIT> - <NUM_LIT>*tau**<NUM_LIT> - <NUM_LIT>*tau**<NUM_LIT:5>)/Tr<EOL>f2 = (-<NUM_LIT>*tau + <NUM_LIT>*tau**<NUM_LIT> - <NUM_LIT>*tau**<NUM_LIT> + <NUM_LIT>*tau**<NUM_LIT:5>)/Tr<EOL>return Pc*exp(f0 + omega*f1 + omega**<NUM_LIT:2>*f2)<EOL>
r'''Calculates vapor pressure of a fluid at arbitrary temperatures using a
    CSP relationship by [1]_; requires a chemical's critical temperature and
    acentric factor.

    The vapor pressure is given by:

    .. math::
        \ln P_r=f^{(0)}+\omega f^{(1)}+\omega^2f^{(2)}

        f^{(0)}=\frac{-5.97616\tau + 1.29874\tau^{1.5}- 0.60394\tau^{2.5}
        -1.06841\tau^5}{T_r}

        f^{(1)}=\frac{-5.03365\tau + 1.11505\tau^{1.5}- 5.41217\tau^{2.5}
        -7.46628\tau^5}{T_r}

        f^{(2)}=\frac{-0.64771\tau + 2.41539\tau^{1.5}- 4.26979\tau^{2.5}
        +3.25259\tau^5}{T_r}

        \tau = 1-T_{r}

    Parameters
    ----------
    T : float
        Temperature of fluid [K]
    Tc : float
        Critical temperature of fluid [K]
    Pc : float
        Critical pressure of fluid [Pa]
    omega : float
        Acentric factor [-]

    Returns
    -------
    Psat : float
        Vapor pressure at T [Pa]

    Notes
    -----
    Somewhat more accurate than the :obj:`Lee_Kesler` formulation.

    Examples
    --------
    Example from [2]_; ethylbenzene at 347.25 K.

    >>> Ambrose_Walton(347.25, 617.15, 36.09E5, 0.304)
    13278.878504306222

    References
    ----------
    .. [1] Ambrose, D., and J. Walton. "Vapour Pressures up to Their Critical
       Temperatures of Normal Alkanes and 1-Alkanols." Pure and Applied
       Chemistry 61, no. 8 (1989): 1395-1403. doi:10.1351/pac198961081395.
    .. [2] Poling, Bruce E. The Properties of Gases and Liquids. 5th edition.
       New York: McGraw-Hill Professional, 2000.