public function callback($primaryCallbackURL)
    {
        if (is_string($primaryCallbackURL)) {
            $this->setPrimaryCallbackURL($primaryCallbackURL)
                ->setSecondaryCallbackURL($primaryCallbackURL);
        }

        return $this;
    }
public function callback($primaryCallbackURL)
    {
        if (is_string($primaryCallbackURL)) {
            $this->setPrimaryCallbackURL($primaryCallbackURL)
                ->setSecondaryCallbackURL($primaryCallbackURL);
        }

        return $this;
    }
public function callback ( $ primaryCallbackURL ) { if ( is_string ( $ primaryCallbackURL ) ) { $ this -> setPrimaryCallbackURL ( $ primaryCallbackURL ) -> setSecondaryCallbackURL ( $ primaryCallbackURL ) ; } return $ this ; }
This method sests a single callback for both the success and Error

@param  string $primaryCallbackURL A url for callbacks from the hubtel server
@return self
This method sests a single callback for both the success and Error