src/Entity/Collection.php
public function offsetExists($key)
    {
        return isset($this->data[$key]) || array_key_exists($key, $this->data);
    }
public function offsetExists($key)
    {
        return isset($this->data[$key]) || array_key_exists($key, $this->data);
    }
public function offsetExists ( $ key ) { return isset ( $ this -> data [ $ key ] ) || array_key_exists ( $ key , $ this -> data ) ; }
Determines whether a item exists.

@param integer $key Key

@return boolean
Determines whether a item exists .