import math


def C_fingas_corr(C, thickness):
    """
    Returns the constant C used in fingas model corrected with the
    slick thickness, used if the slick is less than 1.5 mm
    source : (Fingas, 2015)

    Parameters
    ----------
    C : Fingas constant
    thickness : Slick thickness  [m]


    """
    if thickness > 1.5 / 1000:
        print("Slick thickness is more than 1.5 mm, correction not needed")

    return C + 1 - 0.78 * math.sqrt(thickness/1000)