app\main\views(5).py

from flask import current_app, render_template, flash, redirect, url_for, abort
#...

@main.route('/edit-collection/<int:id>', methods=['GET', 'POST'])
@login_required
def edit_collection(id):
    collection = Collection.query.get_or_404(id)
    if current_user != collection.author and \
            not current_user.can(Permission.ADMIN):
        abort(403)
    form = CollectionForm()
    if form.validate_on_submit():
        # Update Database
        collection.name = form.name.data
        collection.description = form.description.data
        db.session.commit()
        # Update Stream Activity
        if collection.update_stream():
            return redirect(url_for('.edit_collection', id=id))
    form.name.data = collection.name
    form.description.data = collection.description
    return render_template('edit_collection.html', collection=collection, form=form)


@main.route('/delete-collection/<int:id>', methods=['GET', 'POST'])
@login_required
def delete_collection(id):
    collection = Collection.query.get_or_404(id)
    if current_user != collection.author and \
            not current_user.can(Permission.ADMIN):
        abort(403)
    if collection.delete_from_stream():
        db.session.delete(collection)
        db.session.commit()
        flash('Your Collection has been deleted.')
        return redirect(url_for('.index'))
    else:
        flash("An error occurred, please try again")
        return redirect(url_for('.edit_collection', id=collection.id))