BasicReturns: Unified Return Type Models for Python

from typing import Any, Optional
from pydantic import BaseModel

class BasicReturn(BaseModel):
    ok: Optional[bool] = True
    error: Optional[Any] = None

class DataAndMsgReturn(BasicReturn):
    msg: Optional[str] = None
    data: Optional[Any] = None

# ── Without BasicReturns ────────────────────────────────────────────────────

def divide_numbers_old(a: float, b: float):
    """What does this return on failure? A tuple? None? Does it raise?"""
    if b == 0:
        return None          # caller must remember to check for None
    return a / b             # or maybe it raises ZeroDivisionError?

# The caller has no contract to rely on:
result = divide_numbers_old(10, 2)
if result is None:           # fragile — easy to forget
    print("Something went wrong")
else:
    print(result)


# ── With BasicReturns ───────────────────────────────────────────────────────

from BasicReturns import DataAndMsgReturn

def divide_numbers(a: float, b: float) -> DataAndMsgReturn:
    """Always returns a DataAndMsgReturn — callers always know what to expect."""
    response = DataAndMsgReturn()

    try:
        if b == 0:
            raise ZeroDivisionError("Cannot divide by zero")
        response.data = a / b
        response.msg = "Division completed successfully"
    except Exception as e:
        response.ok = False
        response.error = e
        response.msg = "Division failed"

    return response

# The caller has a guaranteed contract:
result = divide_numbers(10, 2)

if result.ok:
    print(f"{result.msg}: {result.data}")   # Division completed successfully: 5.0
else:
    print(f"{result.msg}: {result.error}")  # Division failed: Cannot divide by zero