code: public static String getFirstAuthorizationGrant(RamlAction action, RamlRoot document) {
  		List<String> grants = getAuthorizationGrants(action, document);
  		if (grants.isEmpty()) {
  			return null;
  		}
  		return grants.get(0);
  	}
docs: Returns authorization grant for provided action. It searches for
  authorization grants defined for provided action, some of parent
  resources or the root of the document. If authorization grants found is a
  list - the method will return the first grant in the list.
  
  @param action
  action to find grant for
  @param document
  root raml document
  @return first grant found, null otherwise