docs: function promiseCallback(callback) {
    let _callbackType = _flowRuntime2.default.function();
  
    const _returnType = _flowRuntime2.default.return(_flowRuntime2.default.any());
  
    _flowRuntime2.default.param('callback', _callbackType).assert(callback);
  
    return new Promise((resolve, reject) => {
      callback(resolveFromCallback(resolve, reject));
    }).then(_arg => _returnType.assert(_arg));
  }