from bson import ObjectId
from datetime import datetime

def convert_to_serializable(obj):
    if isinstance(obj, ObjectId):
        return str(obj)
    if isinstance(obj, datetime):
        return obj.isoformat()
    if isinstance(obj, dict):
        return {k: convert_to_serializable(v) for k, v in obj.items()}
    if isinstance(obj, list):
        return [convert_to_serializable(item) for item in obj]
    return obj