code: function normalizeFetchOptions(options) {
    if (options instanceof NodeGit.FetchOptions) {
      return options;
    }
  
    var callbacks;
    var proxyOpts;
  
    if (options) {
      options = shallowClone(options);
      callbacks = options.callbacks;
      proxyOpts = options.proxyOpts;
      delete options.callbacks;
      delete options.proxyOpts;
    } else {
      options = {};
    }
  
    options = normalizeOptions(options, NodeGit.FetchOptions);
  
    if (callbacks) {
      options.callbacks =
        normalizeOptions(callbacks, NodeGit.RemoteCallbacks);
    }
  
    if (proxyOpts) {
      options.proxyOpts =
        normalizeOptions(proxyOpts, NodeGit.ProxyOptions);
    }
    return options;
  }
docs: Normalize an object to match a struct.
  
  @param {String, Object} oid - The oid string or instance.
  @return {Object} An Oid instance.