code: @SuppressWarnings("unchecked")
  	public static <T> Operator<T> createUnionCascade(List<? extends Operator<T>> operators) {
  		return createUnionCascade((Operator<T>[]) operators.toArray(new Operator[operators.size()]));
  	}
docs: Takes a list of operators and creates a cascade of unions of this inputs, if needed.
  If not needed (there was only one operator in the list), then that operator is returned.
  
  @param operators The operators.
  @return The single operator or a cascade of unions of the operators.