MultiValueDictKeyError - Python

{% extends "bc/index.html" %}
{% block form %}
    <div>
        <form action = "" method = "post" class = "registration">
            {% csrf_token %}
            {% if errors %}
                {% for error in errors %}
                    <p>{{error}}</p>
                {% endfor %}
            {% endif %}
            <p><input type = "username" name = "username" placeholder = "Введите логин"></p>
            <p><input type = "password" name = "password" placeholder = "Введите ваш пароль"></p>
            <input type = "submit" value = "войти">
        </form>
    </div>
    {% endblock %}

from django.contrib.auth import login, authenticate, logout
 
def login_user (request):
    user = authenticate (username = request.POST['username'],
                        password = request.POST['password'])
    if user is not None:
        login (request, user)
        return render_to_response ('bc/account_page.html', locals ())
        
    else:
        return render_to_response ('bc/login_page.html')

        from django.contrib.auth import authenticate, login
 
        def my_view(request):
            username = request.POST['username']
            password = request.POST['password']
            user = authenticate(username=username, password=password)
            if user is not None:
                if user.is_active:
                    login(request, user)
                    # Redirect to a success page.
                else:
                    # Return a 'disabled account' error message
            else:
                # Return an 'invalid login' error message.
 
.. admonition:: Calling ``authenticate()`` first