code: public static Function create(String name, String formula, Engine engine) {
          Function result = new Function(name);
          try {
              result.load(formula, engine);
          } catch (RuntimeException ex) {
              throw ex;
          } catch (Exception ex) {
              throw new RuntimeException(ex);
          }
          return result;
      }
docs: Creates a Function term with the given parameters
  
  @param name is the name of the term
  @param formula is the formula defining the membership function
  @param engine is the engine to which the Function can have access
  @return a Function term configured with the given parameters
  
  @throws RuntimeException if the formula has a syntax error