def clean_email(self):
        """ Validate that the e-mail address is unique. """
        if get_user_model().objects.filter(email__iexact=self.cleaned_data['email']):
            if userena_settings.USERENA_ACTIVATION_REQUIRED and UserenaSignup.objects.filter(user__email__iexact=self.cleaned_data['email']).exclude(activation_key=userena_settings.USERENA_ACTIVATED):
                raise forms.ValidationError(_('This email is already in use but not confirmed. Please check your email for verification steps.'))
            raise forms.ValidationError(_('This email is already in use. Please supply a different email.'))
        return self.cleaned_data['email']
Validate that the e-mail address is unique.