src/CacheItem.php
public function expiresAt($expires)
    {
        if ($expires instanceof DateTimeInterface) {
            $this->expires = $expires;
        } else {
            $this->expires = null;
        }
        
        return $this;
    }
public function expiresAt($expires)
    {
        if ($expires instanceof DateTimeInterface) {
            $this->expires = $expires;
        } else {
            $this->expires = null;
        }
        
        return $this;
    }
Sets the expiration time for this cache item.

@param \DateTimeInterface $expires
The point in time after which the item MUST be considered expired.
If null is passed explicitly, a default value MAY be used. If none is set,
the value should be stored permanently or for as long as the
implementation allows.

@return static The called object.