src/common/ṔropertyTrait.php
public function __isset($propertyName)
    {
        $methodName = 'get'.$propertyName;
        if (method_exists($this, $methodName)) {
            return ($this->$methodName() !== null);
        } else {
            return false;
        }
    }
public function __isset($propertyName)
    {
        $methodName = 'get'.$propertyName;
        if (method_exists($this, $methodName)) {
            return ($this->$methodName() !== null);
        } else {
            return false;
        }
    }
Checks if the property is not null
@param type $propertyName