public function getFor($key, \DateTime $date)
    {
        if (!$this->hasFor($key, $date)) {
            return null;
        }

        return $this->data[$this->keyFor($key, $date)];
    }
public function getFor($key, \DateTime $date)
    {
        if (!$this->hasFor($key, $date)) {
            return null;
        }

        return $this->data[$this->keyFor($key, $date)];
    }
public function getFor ( $ key , \ DateTime $ date ) { if ( ! $ this -> hasFor ( $ key , $ date ) ) { return null ; } return $ this -> data [ $ this -> keyFor ( $ key , $ date ) ] ; }
Get value for a key for a given date.

@param string $key Counter key.
@param \DateTime $date Date.
@return float|int|null
Get value for a key for a given date .