text: import invokeMountebankCallback from './invokeMountebankCallback';
  import isEmptyObject from '../utils/isEmptyObject';
  import getDefaultResponse from './getDefaultResponse';
  
  export default async ({
    operationType,
    operationName,
    args,
    headers,
  }) => {
    const stubResponse = await invokeMountebankCallback({
      operationType,
      operationName,
      args,
      headers,
    });
    const {
      response,
      proxy,
    } = stubResponse || {};
    if (isEmptyObject(response) && !proxy) {
      return getDefaultResponse();
    }
    return {
      response,
      proxy,
    };
  };
  