如何在 Django 中使用可选的 URL 参数？

# urls.py
from django.urls import path
from . import views

urlpatterns = [
    path('', views.home, name='home'),
    path('about/', views.about, name='about'),
    path('post/<int:id>/', views.post_detail, name='post_detail'),
    path('search/<str:query>/', views.search, name='search'),
]

# views.py
from django.shortcuts import render

def home(request):
    return render(request, 'home.html')

def about(request):
    return render(request, 'about.html')

def post_detail(request, id):
    return render(request, 'post_detail.html', {'id': id})

def search(request, query):
    return render(request, 'search.html', {'query': query})