one,
    ... }
    >>> first, second = findKnownKerningGroups(testGroups)
    >>> sorted(first) == ['@MMK_L_1', '@MMK_L_2', '@MMK_L_3']
    True
    >>> sorted(second) == ['@MMK_R_1', '@MMK_R_2', '@MMK_R_3']
    True
    r