def local_incid_press(p_inc, rho_cont, h_l, h_ref, gamma_inc=1.1, g=9.81
    ) ->'p_li':
    """Calculate local incidental pressure. Also applicable for 
    local system test pressure.

    :param p_d: $p_d$ design pressure at ref elevation
    :param rho_cont: $\\rho_{cont}$ density of pipeline contents
    :param h_l: $h_l$ elevation of the local pressure point
    :param h_ref: $h_{ref}$ elevation of the reference point
    :param gamma_inc: $\\gamma_{inc}$ incidental to design pressure ratio
    :param g: $g$ gravitational acceleration
    :returns: p_li: $h_{ref}$ local incidental pressure
    
    .. math::
        p_{li} = p_{inc} - \\rho_{cont} \\cdot g \\cdot \\left( h_l - h_{ref} \\right)

    Reference:
    DNVGL-ST-F101 (2017-12) 
        sec:4.2.2.2 eq:4.1 page:67 p_{li}
        sec:4.2.2.2 eq:4.2 page:67 $p_{lt}$ 

    Example:    
    >>> local_incid_press(100.e-5, 1025, -125, 30)
    1558563.751
    """
    p_li = p_inc - rho_cont * g * (h_l - h_ref)
    return p_li
