def remove(self, elem):
        """Remove a requirement.

        :param elem: a string or :class:`Requirement` instance.
        """
        if isinstance(elem, text_type):
            for requirement in self:
                if requirement.package == elem:
                    return super(Requirements, self).remove(requirement)
        return super(Requirements, self).remove(elem)
def add_category():
    form = CategoryForm()

    if form.validate_on_submit():
        form.save()
        flash(_("Category added."), "success")
        return redirect(url_for("management.forums"))

    return render_template("management/category_form.html", form=form,
                           title=_("Add Category"))