Django列出与父类匹配的类实例

我是Django的新手，非常感谢您的帮助。我有一个Gym和二个Route(攀岩馆和攀岩路线(。每个gym可以包含多个routes，但每条路线只能属于一个健身房。我可以列出可用的健身房，然后点击其中一个进入健身房页面，但我想列出所有属于它的路线，但不知道如何列出。

# /gym/models.py
from django.db import models
from django.shortcuts import reverse
class Gym(models.Model):
name = models.CharField(max_length=100)
image = models.ImageField(upload_to='gym', default='default_route.jpg')
address = models.CharField(max_length=200)
def get_absolute_url(self):
return reverse('gym:detail', kwargs={'pk': self.pk})
def __str__(self):
return self.name

# route/models.py
from django.db import models
from .utils import generate_qrcode
class Route(models.Model):
Gym = models.ForeignKey('gym.Gym', on_delete=models.CASCADE, null=True)
grade = models.CharField(max_length=10)
hold_color = models.CharField(max_length=20, default='')
rating = models.PositiveIntegerField()
date = models.DateTimeField(auto_now_add=True)
image = models.ImageField(upload_to='routes', default='default_route.jpg')
def __str__(self):
return str(self.pk)

# gym/views.py
from django.shortcuts import render, get_object_or_404
from django.views.generic import ListView, DetailView
from .models import Gym
from route.models import Route
def gym_list_view(request):
# Can filter this for specific gyms
qs = Gym.objects.all()
return render(request, 'gym/index.html', {'gym_list': qs})
def gym_detail_view(request, pk):
gym_obj = Gym.objects.get(pk=pk)
# This is where I don't know how to get the routes that belong to the current gym
routes_obj = Route.objects.get(pk=pk)
return render(request, 'gym/detail.html', {'gym_object': gym_obj, 'routes_obj': routes_obj})

# gym/templates/gym/detail.html
{% extends "base.html" %}
{% block title %}
{{ gym_object.pk }}
{% endblock title %}
{% block content %}
Gym ID: {{gym_object.pk }} <br><br>
<h3> {{ gym_object.name }} </h3>
{{ gym_object.address }}
<br><br>
<h4>Routes</h4>
route_obj: {{ routes_obj }}
{% endblock content %}