code: func Claim(name string, v interface{}) Option {
  	return func(tok *Bearer) error {
  		if tok.claims == nil {
  			return errors.New("attempting to add claim to improperly created token")
  		}
  
  		tok.claims[name] = v
  
  		return nil
  	}
  }
docs: // Claim is an option that adds an additional claim that is generated with the
  // token.