code: func (e Environment) value(name string) (string, error) {
  	n := e.process(name)
  	v := os.Getenv(n)
  	if v == "" {
  		return v, errors.New("Value does not exist")
  	}
  
  	return v, nil
  }
docs: // value takes a string in normal flag syntax (hello-world) and changes
  // it into a environment variable syntax (HELLO_WORLD). It returns the
  // the value associated with that env.