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