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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def colors_to_materials(colors, count=None):
 """ Convert a list of colors into a list of unique materials and material indexes. Parameters colors : (n, 3) or (n, 4) float RGB or RGBA colors count : int Number of entities to apply color to Returns diffuse : (m, 4) int Colors index : (count,) int Index of each color """


    # convert RGB to RGBA
    rgba = to_rgba(colors)

    # if we were only passed a single color
    if util.is_shape(rgba, (4,)) and count is not None:
        diffuse = rgba.reshape((-1, 4))
        index = np.zeros(count, dtype=np.int)
    elif util.is_shape(rgba, (-1, 4)):
        # we were passed multiple colors
        # find the unique colors in the list to save as materials
        unique, index = grouping.unique_rows(rgba)
        diffuse = rgba[unique]
    else:
        raise ValueError('Colors not convertible!')

    return diffuse, index