docstr: returns the front element of queue.
docstr_tok: ["returns","the","front","element","of","queue","."]
code: def peek(self):
      """returns the front element of queue."""
      if self.is_empty():
          raise IndexError("Queue is empty")
      return self._front.value
  
imports: from abc import ABCMeta, abstractmethod
label_desc: Use image node_id 5 for calling the LinkedListQueue obj's underlying member method code with example usage: obj.peek() and returns: self