code: def commit(self, cb=None):
          '''
          Commit the current transaction.  Caller can specify a callback to use
          when the transaction is committed.
          '''
          # Could call select() but spec 1.9.2.3 says to raise an exception
          if not self.enabled:
              raise self.TransactionsNotEnabled()
  
          self.send_frame(MethodFrame(self.channel_id, 90, 20))
          self._commit_cb.append(cb)
          self.channel.add_synchronous_cb(self._recv_commit_okf commit(self, cb=None):
          '''
          Commit the current transaction.  Caller can specify a callback to use
          when the transaction is committed.
          '''
          # Could call select() but spec 1.9.2.3 says to raise an exception
          if not self.enabled:
              raise self.TransactionsNotEnabled()
  
          self.send_frame(MethodFrame(self.channel_id, 90, 20))
          self._commit_cb.append(cb)
          self.channel.add_synchronous_cb(self._recv_commit_ok)
docs: Commit the current transaction.  Caller can specify a callback to use
          when the transaction is committed.