code: public void addFunctionImport(Class<?> cls) {
          EdmFunctionImport functionImportAnnotation = cls.getAnnotation(EdmFunctionImport.class);
          FunctionImportImpl.Builder functionImportBuilder = new FunctionImportImpl.Builder()
                  .setEntitySetName(functionImportAnnotation.entitySet())
                  .setFunctionName(functionImportAnnotation.namespace() + "." + functionImportAnnotation.function())
                  .setIncludeInServiceDocument(functionImportAnnotation.includeInServiceDocument())
                  .setName(functionImportAnnotation.name())
                  .setJavaClass(cls);
  
          functionImportBuilders.add(functionImportBuilder);
      }
docs: Add function import to builder of this factory by specified class.
  @param cls    function import class