code: public function __isset($property)
      {
          trigger_error(
              sprintf(
                  'Using isset() with entity properties is deprecated. Use %s::notEmpty("%s") instead.',
                  get_class($this),
                  $property
              ),
              E_USER_DEPRECATED
          );
          return $this->notEmpty($property);
      }
docs: Checks if a property exists and has a non-empty value.
  
  If the property is an array, the check will return, if this
  array has items or not.
  
  @deprecated since 0.25 Use {@link notEmpty()}
  @param string $property
  @return boolean