def get_opposite_azimuth(myazi, tolerance=20):
    """
    Get the opposite azimuth plus/minus a tolerance.

    To be a reference radial, four criteria must be met.
    Second, these two initial reference radials should be separated by
    approximately 180.

    Parameters:
    ===========
    myazi: int
        Azimuth angle.
    tolerance: int
        Range of tolerance for the azimuth.

    Returns:
    ========
    minazi: int
        Opposite angle minimun range
    maxazi: int
        Opposite angle maximum range
    """
    azi_range = 180 - tolerance
    minazi = myazi + azi_range
    maxazi = myazi - azi_range
    if minazi > 360:
        minazi -= 360
    if maxazi < 0:
        maxazi += 360

    return [minazi, maxazi]