code: def clean(self):
          
          identification = self.cleaned_data.get('identification')
          password = self.cleaned_data.get('password')
  
          if identification and password:
              user = authenticate(identification=identification, password=password)
              if user is None:
                  raise forms.ValidationError(_("Please enter a correct username or email and password. Note that both fields are case-sensitive."))
          return self.cleaned_data
docs: Checks for the identification and password.
  
          If the combination can't be found will raise an invalid sign in error.