private function buildGroup($group)
    {
        if (is_null($group)) {
            $group = [
                'filter' => [
                    'is_to_all' => true,
                ],
            ];
        } elseif (is_array($group)) {
            $group = [
                'touser' => $group,
            ];
        } else {
            $group = [
                'filter' => [
                    'is_to_all' => false,
                    'group_id' => $group,
                ],
            ];
        }

        return $group;
    }
private function buildGroup($group)
    {
        if (is_null($group)) {
            $group = [
                'filter' => [
                    'is_to_all' => true,
                ],
            ];
        } elseif (is_array($group)) {
            $group = [
                'touser' => $group,
            ];
        } else {
            $group = [
                'filter' => [
                    'is_to_all' => false,
                    'group_id' => $group,
                ],
            ];
        }

        return $group;
    }
private function buildGroup ( $ group ) { if ( is_null ( $ group ) ) { $ group = [ 'filter' => [ 'is_to_all' => true , ] , ] ; } elseif ( is_array ( $ group ) ) { $ group = [ 'touser' => $ group , ] ; } else { $ group = [ 'filter' => [ 'is_to_all' => false , 'group_id' => $ group , ] , ] ; } return $ group ; }
Build group.

@param mixed $group

@return array
Build group .