Determines if any single alternative subset in {@code altsets} contains
exactly one alternative.
@param altsets a collection of alternative subsets
@return {@code true} if {@code altsets} contains a {@link BitSet} with
{@link BitSet#cardinality cardinality} 1, otherwise {@code false}
Determines if any single alternative subset in {@code altsets} contains exactly one alternative.
@param altsets a collection of alternative subsets @return {@code true} if {@code altsets} contains a {@link BitSet} with {@link BitSet#cardinality cardinality} 1, otherwise {@code false}