original_string: public function channel($channelId = null)
      {
          if (isset($this->channels[$channelId])) {
              return $this->channels[$channelId];
          } else {
              $channelId = $channelId ? : $this->getFreeChannelId();
              $ch = new Channel($this->connection, $channelId);
              return $this->channels[$channelId] = $ch;
          }
      }
code: public function channel($channelId = null)
      {
          if (isset($this->channels[$channelId])) {
              return $this->channels[$channelId];
          } else {
              $channelId = $channelId ? : $this->getFreeChannelId();
              $ch = new Channel($this->connection, $channelId);
              return $this->channels[$channelId] = $ch;
          }
      }
code_tokens: public function channel ( $ channelId = null ) { if ( isset ( $ this -> channels [ $ channelId ] ) ) { return $ this -> channels [ $ channelId ] ; } else { $ channelId = $ channelId ? : $ this -> getFreeChannelId ( ) ; $ ch = new Channel ( $ this -> connection , $ channelId ) ; return $ this -> channels [ $ channelId ] = $ ch ; } }
docstring: Fetch a Channel object identified by the numeric channel_id, or
  create that object if it doesn't already exist.
  
  @param string|null $channelId
  
  @return \AMQP\Channel
docstring_tokens: Fetch a Channel object identified by the numeric channel_id or create that object if it doesn t already exist .