code: function _isPropertyNestedObject(o, k) {
      return !!o && o.hasOwnProperty(k) && typeof o[k] === "object" && o[k] !== null && !isEmptyObject(o[k]);
  }
docs: Checks whether a certain object property is from object type and is a non empty object.
  @param  {Object} o - the object.
  @param  {string} k - the object property.
  @returns {boolean} returns true if o[k] is an non empty object.
  @memberof utils