diff --git a/flask-mongo/app.py b/flask-mongo/app.py
index 8a6418b..5b10461 100644
--- a/flask-mongo/app.py
+++ b/flask-mongo/app.py
@@ -1,13 +1,10 @@
 from flask import Flask, request, jsonify
 from pymongo import MongoClient
 from flask_cors import CORS
-import collections.abc
-
 
 app = Flask(__name__)
 cors = CORS(app, resources={r"/api/*": {"origins": "*"}})
 
-# Connect to MongoDB
 client = MongoClient('mongodb://mongo:27017/')
 db = client['studentsdb']
 students_collection = db['students']
@@ -20,24 +17,34 @@ def get_students():
 @app.route('/students/<student_id>', methods=['GET'])
 def get_student(student_id):
     student = students_collection.find_one({'student_id': student_id}, {'_id': 0})
+    if not student:
+        return jsonify({'error': 'Student not found'}), 404
     return jsonify(student)
 
 @app.route('/students', methods=['POST'])
 def create_student():
-    new_student = request.json
+    if not request.is_json:
+        return jsonify({'error': 'Request must be JSON'}), 400
+    new_student = request.get_json()
     students_collection.insert_one(new_student)
-    return jsonify({'message': 'Student created successfully'})
+    return jsonify({'message': 'Student created successfully'}), 201
 
 @app.route('/students/<student_id>', methods=['PUT'])
 def update_student(student_id):
-    updated_student = request.json
-    students_collection.update_one({'student_id': student_id}, {'$set': updated_student})
+    if not request.is_json:
+        return jsonify({'error': 'Request must be JSON'}), 400
+    updated_student = request.get_json()
+    result = students_collection.update_one({'student_id': student_id}, {'$set': updated_student})
+    if result.matched_count == 0:
+        return jsonify({'error': 'Student not found'}), 404
     return jsonify({'message': 'Student updated successfully'})
 
 @app.route('/students/<student_id>', methods=['DELETE'])
 def delete_student(student_id):
-    students_collection.delete_one({'student_id': student_id})
+    result = students_collection.delete_one({'student_id': student_id})
+    if result.deleted_count == 0:
+        return jsonify({'error': 'Student not found'}), 404
     return jsonify({'message': 'Student deleted successfully'})
 
 if __name__ == '__main__':
-    app.run(host='0.0.0.0', port=6000, debug=True)
+    app.run(host='0.0.0.0', port=6000, debug=True)
\ No newline at end of file