def SplitMask(mask, mask_1_length):
    """
    

    Parameters
    ----------
    mask : tuple
        tuple of n 1d array of size s, coordonate of s points.
    mask_1_length : int
        length of mask_1 after spliting

    Returns
    -------
    mask_1 : tuple
        tuple of n 1d array of size mask_1_length, coordonate of points
    mask_2 : tuple
        tuple of n 1d array of size s - mask_1_length, coordonate of points.

    """
    mask_1 = []
    mask_2 = []
    for i in range(len(mask)):
        mask_1.append(mask[i][0:mask_1_length])
        mask_2.append(mask[i][mask_1_length:])
    mask_1 = tuple(mask_1)
    mask_2 = tuple(mask_2)
    return mask_1, mask_2