async loadFixtures(fixtures = {}, { refresh = "wait_for" } = {}) {
    if (!isPlainObject(fixtures)) {
      throw kerror.get("api", "assert", "invalid_argument", fixtures, "object");
    }

    for (const index of Object.keys(fixtures)) {
      if (!isPlainObject(fixtures[index])) {
        throw kerror.get(
          "api",
          "assert",
          "invalid_argument",
          fixtures[index],
          "object",
        );
      }

      for (const [collection, payload] of Object.entries(fixtures[index])) {
        this.cache.assertCollectionExists(index, collection);

        const { errors } = await this.client.import(
          index,
          collection,
          payload,
          { refresh },
        );

        if (errors.length > 0) {
          throw servicesError.get("import_failed", errors);
        }
      }
    }
  }
Load database fixtures into Kuzzle

@param {String} fixturesId
@returns {Promise}