code: public static <T, U> List<U> map(Collection<T> inputs, Mapper<T, U> mapper) {
  		if (inputs == null) {
  			return null;
  		}
  
  		List<U> outputs = new ArrayList<>(inputs.size());
  		for (T input : inputs) {
  			outputs.add(mapper.apply(input));
  		}
  
  		return outputs;
  	}
docs: Map input values to output values.
  
  @param inputs Input values.
  @param mapper Mapper function.
  @param <T> Type of input values.
  @param <U> Type of output values.
  @return Output values.