如何在Django中添加显示下拉字段

from django.db import models

class Book(models.Model):
    GENRE_CHOICES = (
        ('F', 'Fiction'),
        ('N', 'Non-fiction'),
        ('M', 'Mystery'),
        ('R', 'Romance'),
    )
    genre = models.CharField(max_length=1, choices=GENRE_CHOICES)
    # 其他属性...

from django import forms
from .models import Book

class BookForm(forms.ModelForm):
    class Meta:
        model = Book
        fields = ['genre']

from django.shortcuts import render
from .forms import BookForm

def add_book(request):
    if request.method == 'POST':
        form = BookForm(request.POST)
        if form.is_valid():
            form.save()
            # 处理表单提交成功后的逻辑
    else:
        form = BookForm()
    return render(request, 'add_book.html', {'form': form})

<form method="post">
  {% csrf_token %}
  {{ form.as_p }}
  <button type="submit">提交</button>
</form>