public static boolean hasConflictingAltSet(Collection<BitSet> altsets) {
		for (BitSet alts : altsets) {
			if ( alts.cardinality()>1 ) {
				return true;
			}
		}
		return false;
	}
Determines if any single alternative subset in {@code altsets} contains
more than one alternative.

@param altsets a collection of alternative subsets
@return {@code true} if {@code altsets} contains a {@link BitSet} with
{@link BitSet#cardinality cardinality} &gt; 1, otherwise {@code false}
runtime/Java/src/org/antlr/v4/runtime/atn/PredictionMode.java