public function removeFor($key, \DateTime $date)
    {
        unset($this->data[$this->keyFor($key, $date)]);
    }
public function removeFor($key, \DateTime $date)
    {
        unset($this->data[$this->keyFor($key, $date)]);
    }
public function removeFor ( $ key , \ DateTime $ date ) { unset ( $ this -> data [ $ this -> keyFor ( $ key , $ date ) ] ) ; }
Remove value for a key for a given date.

@param string $key Counter key.
@param \DateTime $date Date.
@return void
Remove value for a key for a given date .