public boolean containsFast(ATNConfig obj) {
		if (configLookup == null) {
			throw new UnsupportedOperationException("This method is not implemented for readonly sets.");
		}

		return configLookup.containsFast(obj);
	}
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