def METHOD_NAME(self):
    email = self.cleaned_data.get("email")
    password = self.cleaned_data.get("password")
    email = email.lower()
    if email and password:
        self.user_cache = authenticate(email=email, password=password)
        if self.user_cache is None:
            raise forms.ValidationError(_("Please enter a correct email and password."))
    self.check_for_test_cookie()
    return password