code: function nativeKeysIn(object) {
      var result = [];
      if (object != null) {
        for (var key in Object(object)) {
          result.push(key);
        }
      }
      return result;
    }
docs: This function is like
  [`Object.keys`](http://ecma-international.org/ecma-262/7.0/#sec-object.keys)
  except that it includes inherited enumerable properties.
  
  @private
  @param {Object} object The object to query.
  @returns {Array} Returns the array of property names.