Python Django没有返回表单中的语言模型

我正在本地图书馆上进行由MDN编写的Django教程

在语言模型的管理站点中，我并没有收到任何返回的错误，在那个里我必须为书籍选择语言

但在呈现书籍细节时，用户站点上的语言模型反映了错误

错误：

语言：catalog.Language.none

代码和模型详细信息如下所示

<p><strong>Author:</strong> <a href="{{ book.author.get_absolute_url }}">{{ book.author }}</a></p>
    <p><strong>Summary:</strong> {{ book.summary }}</p>
    <p><strong>ISBN:</strong> {{ book.isbn }}</p> 
    <p><strong>Language:</strong> {{ book.language }}</p>
    <p><strong>Genre:</strong> {{ book.genre.all|join:", " }}</p>

类语言的models.py

class Language(models.Model):
    name = models.CharField(max_length=200, help_text='Enter a book language(e.g. English)')
    
    def __str__(self):
        return self.name

models.py用于教科书

class Book(models.Model):
    """Model representing a book (but not a specific copy of a book)."""
    title = models.CharField(max_length=200)
    author = models.ForeignKey('Author', on_delete=models.SET_NULL, null=True)

    summary = models.TextField(
        max_length=1000, help_text='Enter a brief description of the book')
    isbn = models.CharField('ISBN', max_length=13, unique=True,
                            help_text='13 Character <a href="https://www.isbn-international.org/content/what-isbn">ISBN number</a>')

    genre = models.ManyToManyField(
        Genre, help_text='Select a genre for this book')
    
    language = models.ManyToManyField(
        Language, help_text='Select Language for this book')
    
    def get_language(self):
        return ', '.join(language.name for language in self.language.all())

    get_language.short_description = 'Language'
    
    class Meta:
        ordering = ['title', 'author']
    
    def __str__(self):
        return self.title

    def get_absolute_url(self):
        return reverse('book-detail', kwargs= {'pk': str(self.id)})
    
    def display_genre(self):
        return ', '.join(genre.name for genre in self.genre.all()[:3])

    display_genre.short_description = 'Genre'

图书细节视图模型

class BookListView(ListView):
    model = Book

class BookDetailView(DetailView):
    model = Book

书籍详细视图的HTML如下所示

<p><strong>Author:</strong> <a href="{{ book.author.get_absolute_url }}">{{ book.author }}</a></p>
    <p><strong>Summary:</strong> {{ book.summary }}</p>
    <p><strong>ISBN:</strong> {{ book.isbn }}</p> 
    <p><strong>Language:</strong> {{ book.language }}</p>
    <p><strong>Genre:</strong> {{ book.genre.all|join:", " }}</p>

作者：

摘要：{{book.Summary}

ISBN:{{book.ISBN}}

语言：{{book.Language}

流派：{{book.Genre.all |加入：“，”}

---

谢谢你

我想你需要

语言：{{book.get\u Language}}
。谢谢@evergreen它成功了