def METHOD_NAME(self):
    if any(self.errors):
        return
    contents = []
    duplicates = False
    has_correct = False
    for form in self.forms:
        content = form.cleaned_data['content']
        is_correct = form.cleaned_data['is_correct']
        if content:
            if content in contents:
                duplicates = True
            contents.append(content)
            if duplicates:
                raise forms.ValidationError(_("The alternatives must not be equals."), code = 'duplicate_alternatives')
            if has_correct:
                if is_correct is True:
                    raise forms.ValidationError(_("Only one alternative must be correct."), code = 'multiple_correct')
                else:
                    has_correct = True
            else:
                if is_correct is True:
                    has_correct = True
    if has_correct is False:
        raise forms.ValidationError(_("You must provide the correct answer."), code = 'correct_answer'