Python 我得到一个'；没有名为django'的模块；只有当我尝试提交电子邮件表单时，heroku上才出现错误，但在本地它工作正常

当我在heroku控制台上pip freeze时，我发现已经安装了django。 当我尝试在本地计算机上提交表单时，提交成功，没有错误

视图.py

    '''

    @login_required(login_url='/accounts/login/')
def b_contact(request):
c_form = ContactForm
if request.method == 'POST':
    c_form = ContactForm(data=request.POST)
    if c_form.is_valid():
        email = c_form.cleaned_data['email']
        subject = c_form.cleaned_data['subject']
        message = c_form.cleaned_data['message'] 
        send_mail(email, message, subject, ['be.rightmuk@gmail.com'], fail_silently=False)
        messages.success(request, f'Your message has been sent!')
        return redirect('buyer_home')
else:
    email = request.POST.get('email')
    subject = request.POST.get('subject')
    message = request.POST.get('message')

context = {
    'c_form': c_form
} 

return render(request, 'buyer/contact.html', context)

 class ContactForm(forms.Form):
email = forms.EmailField(label='Your Email')
subject = forms.CharField(required=True, max_length=150)
message = forms.CharField(widget=forms.Textarea, required=True)

'''

forms.py

    '''

    @login_required(login_url='/accounts/login/')
def b_contact(request):
c_form = ContactForm
if request.method == 'POST':
    c_form = ContactForm(data=request.POST)
    if c_form.is_valid():
        email = c_form.cleaned_data['email']
        subject = c_form.cleaned_data['subject']
        message = c_form.cleaned_data['message'] 
        send_mail(email, message, subject, ['be.rightmuk@gmail.com'], fail_silently=False)
        messages.success(request, f'Your message has been sent!')
        return redirect('buyer_home')
else:
    email = request.POST.get('email')
    subject = request.POST.get('subject')
    message = request.POST.get('message')

context = {
    'c_form': c_form
} 

return render(request, 'buyer/contact.html', context)

 class ContactForm(forms.Form):
email = forms.EmailField(label='Your Email')
subject = forms.CharField(required=True, max_length=150)
message = forms.CharField(widget=forms.Textarea, required=True)

template

    <form method="POST">
    {% csrf_token %}
    <fieldset class="form-group">

        {{ c_form|crispy }}
    </fieldset>

        <button class="btn btn-default" type="submit">Send </button>

</form> 

这是错误

ModuleNotFoundError at /seller/contact/
No module named "'django"
Request Method: POST
Request URL:     
https://sakka.herokuapp.com/seller/contact/
Django Version: 2.0
Exception Type: ModuleNotFoundError
Exception Value:    
No module named "'django"
Exception Location: <frozen importlib._bootstrap> in 
_find_and_load_unlocked, line 953
Python Executable:  /app/.heroku/python/bin/python
Python Version: 3.6.8
Python Path:    
['/app/.heroku/python/bin',
'   /app',
'/app/.heroku/python/lib/python36.zip',
'/app/.heroku/python/lib/python3.6',
'/app/.heroku/python/lib/python3.6/lib-dynload',
'/app/.heroku/python/lib/python3.6/site-packages']
Server time:    Thu, 24 Oct 2019 15:06:42 +0300

moduleNotFound在/卖方/联系人处出错/
没有名为“django”的模块
申请方式：邮寄
请求URL:
https://sakka.herokuapp.com/seller/contact/
Django版本：2.0
异常类型：ModuleNotFoundError
异常值：
没有名为“django”的模块
异常位置：在
_第953行，查找并加载解锁
Python可执行文件：/app/.heroku/Python/bin/Python
Python版本：3.6.8
Python路径：
['/app/.heroku/python/bin'，
“/app”，
“/app/.heroku/python/lib/python36.zip”，
“/app/.heroku/python/lib/python3.6”，
“/app/.heroku/python/lib/python3.6/lib dynload”，
'/app/.heroku/python/lib/python3.6/site packages']
服务器时间：2019年10月24日星期四15:06:42+0300

只有当我试图从我的联系方式中发布一些信息时，这个错误才会出现，否则其他一切都正常