def drop_zeroes_errors(X, Y, Z):
    """ Drops data points where y = 0 or z = 0"""
    x_dropped = []
    y_dropped = []
    z_dropped = []
    for x, y, z in zip(X, Y, Z):
        if y != 0 or z != 0:
            x_dropped.append(x)
            y_dropped.append(y)
            z_dropped.append(z)
    return x_dropped, y_dropped, z_dropped