def borders(det):
    """
    Calculates the borders for image
    
    Parameters
    --------------
    det: int array
        Detected face
    
    Returns
    ----------------------
    l: int list
        Coordinates for left bound of border
    r: int list
        Coordinates for right bound of border
    t: int list
        Coordinates for top bound of border
    b: int list
        Coordinates for bottom bound of border
    """
    l, r, t, b = det.left(), det.right(), det.top(), det.bottom()
    return l, r, t, b