@Override
	public void clear() {
		if ( readonly ) throw new IllegalStateException("This set is readonly");
		configs.clear();
		cachedHashCode = -1;
		configLookup.clear();
	}
Gets the complete set of represented alternatives for the configuration
set.

@return the set of represented alternatives in this configuration set

@since 4.3
runtime/Java/src/org/antlr/v4/runtime/atn/ATNConfigSet.java