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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def signup(request, **kwargs):
 """ Overrides allauth.account.views.signup """

    if not ALLAUTH:
        return http.HttpResponse(_('allauth not installed...'))
    if request.method == "POST" and 'login' in request.POST:
        form_class = LoginForm
        form = form_class(request.POST)
        redirect_field_name = "next"
        success_url = get_default_redirect(request, redirect_field_name)
        if form.is_valid():
            return form.login(request, redirect_url=success_url)
    response = allauth_signup(request, **kwargs)
    return response