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Errors & debugging

Handle failures gracefully, raise helpful errors, and debug with confidence.

3 matches

How to Use Optional Return in Python Instead of Raising Exceptions

A Python function returns None for missing dictionary keys instead of raising KeyError, enabling graceful lookup handling with type hints.

optional typing dict-get

Python

from typing import Optional


def find_user(users: dict, user_id: int) -> Optional[dict]:
    """
    Look up a user by ID. Returns the user dict if found,
    otherwise returns None instead of raising KeyError.
    """
    return users.get(user_id)


def main() -> None:
    users = {
        1: {"name": "Alice", "ema…

14 0 Open

Errors & debugging easy

How to Wrap a Low Level Error in a Higher Level Exception in Python

Wrap low-level exceptions in a higher-level exception while preserving the original cause with the `from` keyword.

exception-chaining error-handling wrapping

Python

class LowLevelError(Exception):
    pass

class HighLevelError(Exception):
    pass

def low_level_operation():
    raise LowLevelError("storage drive failed to respond")

def high_level_operation():
    try:
        low_level_operation()
    except LowLevelError as e:
        raise HighLevelError(f"database operation…

12 0 Open

Errors & debugging easy

Map Exception Type to HTTP Status Code in Python

Maps Python exception types to appropriate HTTP status codes using a dictionary lookup for consistent API error handling.

exceptions http-status error-handling

Python

EXCEPTION_STATUS_MAP = {
    ValueError: 400,
    KeyError: 400,
    TypeError: 400,
    PermissionError: 403,
    FileNotFoundError: 404,
    AttributeError: 404,
    TimeoutError: 408,
    NotImplementedError: 501,
    ConnectionError: 503,
}


def status_code_for(exception_type):
    try:
        return EXCEPTION_S…

13 0 Open

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