PaperParser/app/blueprints/api/collections/routes.py

from flask import Blueprint, render_template, request

from app.models.collection import Collection
from app.extensions import db

collections = Blueprint("collections", __name__, url_prefix="/collections", template_folder="templates")

@collections.route("/<int:id>", methods=["DELETE"])
def delete_collection(id: int):
    
    collection: Collection = Collection.query.get_or_404(id)

    length = len(Collection.query.all()) - 1
    
    db.session.delete(collection)
    db.session.commit()
    
    if length <= 0:
        return "<small class=\"form-text\">Здесь ничего нет</small>", 200
    
    return "", 204