protected function getChannels($channels)
    {
        $channels = trim($channels);

        if (empty($channels)) {
            throw new InvalidArgumentException('No channel found.');
        }

        return $channels === '*' ? [] : explode(',', $channels);
    }
protected function getChannels($channels)
    {
        $channels = trim($channels);

        if (empty($channels)) {
            throw new InvalidArgumentException('No channel found.');
        }

        return $channels === '*' ? [] : explode(',', $channels);
    }
protected function getChannels ( $ channels ) { $ channels = trim ( $ channels ) ; if ( empty ( $ channels ) ) { throw new InvalidArgumentException ( 'No channel found.' ) ; } return $ channels === '*' ? [ ] : explode ( ',' , $ channels ) ; }
Convert channels string to channel list.

@param  string $channels
@return array
Convert channels string to channel list .