public function setCreatedAt($created_at) {

        $this -> created_at = $created_at !== null ? new \DateTime($created_at) : null;
        return $this;
    }
public function setCreatedAt($created_at) {

        $this -> created_at = $created_at !== null ? new \DateTime($created_at) : null;
        return $this;
    }
public function setCreatedAt ( $ created_at ) { $ this -> created_at = $ created_at !== null ? new \ DateTime ( $ created_at ) : null ; return $ this ; }
Sets the created at
@param string $created_at
@return TimestampAwareTrait
Sets the created at