def plugin_test_validation(self, handler):
        """Plugin validation.
        
        Every workbench plugin must have top level test method.

        Args:
            handler: The loaded plugin.

        Returns:
            None if the test fails or the test function.
        """
        methods = {name:func for name, func in inspect.getmembers(handler, callable)}
        if 'test' not in methods.keys():
            print (handler.__name__) % 'Failure for plugin: %s'
            print 'Validation Error: The file must have a top level test() method'
            return None
        else:
            return methods['test']
dataset/ETHPy150Open SuperCowPowers/workbench/workbench/server/plugin_manager.py/PluginManager.plugin_test_validation/swapped operands of `%`