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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 validate_cmaps(cmaps):
 """Validate a dictionary of color lists Parameters cmaps: dict a mapping from a colormap name to a list of colors Raises ------ ValueError If one of the values in `cmaps` is not a color list Notes ----- For all items (listname, list) in `cmaps`, the reversed list is automatically inserted with the ``listname + '_r'`` key."""

    cmaps = {validate_str(key): validate_colorlist(val) for key, val in cmaps}
    for key, val in six.iteritems(cmaps):
        cmaps.setdefault(key + '_r', val[::-1])
    return cmaps