def get_spaced_colors(n, alpha):
    """ 
    Helper function. 
    Generate a list of different colors (as RGBA format) with given alpha

    """

    max_value = 16581375 #255**3
    interval = int(max_value / n)
    colors = [hex(I)[2:].zfill(6) for I in range(0, max_value, interval)]
    RGBA_colors = [(int(i[1::3], 16)/255, int(i[0::3], 16)/255, int(i[2::3], 16)/255, alpha) for i in colors]    

    return RGBA_colors