Reference library

Errors & debugging

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

3 matches

How to Emit Deprecation Warnings in Python

Use the warnings module to mark legacy classes and methods as deprecated, letting users know to switch to newer APIs.

import warnings


class OldAPI:
    def __init__(self):
        warnings.warn(
            "OldAPI is deprecated; use NewAPI instead.",
            DeprecationWarning,
            stacklevel=2,
        )
        self.data = []

    def add(self, item):
        warnings.warn(
            "OldAPI.add() is deprecated; us…

14 0 Open

Errors & debugging easy

Implement a Context Manager That Suppresses Exceptions in Python

Shows how to write a custom context manager that catches specified exceptions and optionally re-raises others, plus the stdlib contextlib.suppress alternative.

context-manager exception-handling with-statement

Python

import contextlib

class SuppressExceptions:
    def __init__(self, *exceptions):
        self.exceptions = exceptions

    def __enter__(self):
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        if exc_type is None:
            return False
        if not self.exceptions or exc_type in se…

11 0 Open

Errors & debugging easy

Log to stderr with Python logging basicConfig

Configure Python's logging module to send all log messages to standard error (stderr) instead of the default stderr, with a readable timestamped format.

logging stderr debugging

Python

import logging

def main():
    logging.basicConfig(
        level=logging.DEBUG,
        format="%(asctime)s — %(name)s — %(levelname)s — %(message)s",
        stream=__import__("sys").stderr,
    )
    logger = logging.getLogger("example")
    logger.debug("Debug message")
    logger.info("Info message")
    logger.…

12 0 Open

Browse by section

Each section groups closely related Python snippets.