     }
    ... }
    >>> kerning == expected
    True
    >>> expected = {
    ...     "@MMK_L_BGroup": ["B"],
    ...     "@MMK_L_CGroup": ["C"],
    ...     "@MMK_L_XGroup": ["X"],
    ...     "@MMK_R_CGroup": ["C"],
    ...     "@MMK_R_DGroup": ["D"],
    ...     "@MMK_R_XGroup": ["X"],
    ...     "public.kern1.BGroup": ["B"],
    ...     "public.kern1.CGroup": ["C"],
    ...     "public.kern1.XGroup": ["X"],
    ...     "public.kern2.CGroup": ["C"],
    ...     "public.kern2.DGroup": ["D"],
    ...     "public.kern2.XGroup": ["X"],
    ... }
    >>> groups == expected
    True

    >>> from .validators import kerningValidator
    >>> kerningValidator(kerning)
    (True, None)

    Mixture of known prefixes and groups without prefixes.

    >>> testKerning = {
    ...     "A" : {
    ...         "A" : 1,
    ...         "B" : 2,
    ...         "@MMK_R_CGroup" : 3,
    ...         "DGroup" : 4
    ...     },
    ...     "BGroup" : {
    ...         "A" : 5,
    ...         "B" : 6,
    ...         "@MMK_R_CGroup" : 7,
    ...         "DGroup" : 8
    ...     },
    ...     "@MMK_L_CGroup" : {
    ...         "A" : 9,
    ...         "B" : 10,
    ...         "@MMK_R_CGroup" : 11,
    ...         "DGroup" : 12
    ...     },
    ... }
    >>> testGroups = {
    ...     "BGroup" : ["B"],
    ...     "@MMK_L_CGroup" : ["C"],
    ...     "@MMK_R_CGroup" : ["C"],
    ...     "DGroup" : ["D"],
    ... }
    >>> kerning, groups, maps = convertUFO1OrUFO2KerningToUFO3Kerning(
    ...     testKerning, testGroups, [])
    >>> expected = {
    ...     "A" : {
    ...         "A": 1,
    ...         "B": 2,
    ...         "public.kern2.CGroup": 3,
    ...         "public.kern2.DGroup": 4
    ...     },
    ...     "public.kern1.BGroup": {
    ...         "A": 5,
    ...         "B": 6,
    ...         "public.kern2.CGroup": 7,
    ...         "public.kern2.DGroup": 8
    ...     },
    ...     "public.kern1.CGroup": {
    ...         "A": 9,
    ...         "B": 10,
    ...         "public.kern2.CGroup": 11,
    ...         "public.kern2.DGroup": 12
    ...     }
    ... }
    >>> kerning == expected
    True
    >>> expected = {
    ...     "BGroup": ["B"],
    ...     "@MMK_L_CGroup": ["C"],
    ...     "@MMK_R_CGroup": ["C"],
    ...     "DGroup": ["D"],
    ...     "public.kern1.BGroup": ["B"],
    ...     "public.kern1.CGroup": ["C"],
    ...     "public.kern2.CGroup": ["C"],
    ...     "public.kern2.DGroup": ["D"],
    ... }
    >>> groups == expected
    True
    Nr