def check_data_1d(x, y):
    """
    Performs consistency checks on the data passed into make_film_1d.

    These checks are only done when both x and y arguments are passed into the
    function.

    Parameters
    ----------

    x : array_like,
        Array specifying the x axis.
    y : array_like
        Two dimensional array assumed to be of the form y(t, x). This specifies
        the values to be plotted as a function of time.
    """
    x_s = x.shape
    y_s = y.shape
    if len(x_s) != 1:
        raise IndexError('x must be one dimensional.')
    if len(y_s) != 2:
        raise IndexError('y must be two dimensional.')
    if x_s[0] != y_s[1]:
        raise ValueError('x and y must have the same length: {0}, {1}'.
            format(x_s[0], y_s[1]))
