docs: def clear_queue(self, trans_id=None):
  		''' Clear the queue of database operations without executing any of
  			 the pending operations'''
  		if not self.queue:
  			return
  		if trans_id is None:
  			self.queue = []
  			return
  
  		for index, op in enumerate(self.queue):
  			if op.trans_id == trans_id:
  				break
  		self.queue = self.queue[:index]