def squish(incs, f):
    """
    returns 'flattened' inclination, assuming factor, f and King (1955) formula:
    tan (I_o) = f tan (I_f)

    Parameters
    __________
    incs : array of inclination (I_f)  data to flatten
    f : flattening factor

    Returns
    _______
    I_o :  inclinations after flattening
    """
    incs = np.radians(incs)
    I_o = f * np.tan(incs)  # multiply tangent by flattening factor
    return np.degrees(np.arctan(I_o))