code: @Override
      public <T> T getInterface(Class<T> clasz) {
          return clasz.cast(getGlobal().getInterface(clasz));
      }
docs: Returns an implementation of an interface using procedures compiled in the
  interpreter. The methods of the interface may be implemented using the
  {@code invoke} method.
  
  @param clasz The {@code Class} object of the interface to return.
  @return An instance of requested interface - null if the requested interface
  is unavailable, i. e. if compiled methods in the
  {@code ScriptEngine} cannot be found matching the ones in the
  requested interface.
  @throws IllegalArgumentException if the specified {@code Class} object
  does not exist or is not an interface.