How to Build a Simple Data Helper Class in Python

import json
from dataclasses import dataclass, asdict
from pathlib import Path

@dataclass
class User:
    name: str
    age: int
    email: str

class DataHelper:
    def __init__(self, filepath: str = "data.json"):
        self.filepath = Path(filepath)
        self._data = self._load()
    
    def _load(self) -> list:
        if self.filepath.exists():
            with open(self.filepath, "r") as f:
                return json.load(f)
        return []
    
    def save(self) -> None:
        with open(self.filepath, "w") as f:
            json.dump(self._data, f, indent=2)
        print(f"Saved {len(self._data)} records to {self.filepath}")
    
    def add(self, item: User) -> None:
        self._data.append(asdict(item))
        self.save()
    
    def get_all(self) -> list:
        return self._data

def main():
    helper = DataHelper("users.json")
    helper.add(User("Alice", 30, "alice@example.com"))
    helper.add(User("Bob", 25, "bob@example.com"))
    print("All users:", helper.get_all())

if __name__ == "__main__":
    main()