Reference library

Errors & debugging

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

4 matches

How to Assert Preconditions with Descriptive Messages in Python

Use Python's assert statement with a custom message to validate function preconditions and fail fast with clear diagnostics.

assert debugging preconditions

Python

def divide(dividend, divisor):
    assert divisor != 0, f"Divisor must be non-zero, got {divisor!r}"
    return dividend / divisor


if __name__ == "__main__":
    print(divide(10, 2))
    try:
        divide(10, 0)
    except AssertionError as e:
        print(f"AssertionError: {e}")

16 0 Open

Errors & debugging easy

How to Build an Error Code Enum in Python

Define an API error code enum with descriptions and build structured error payloads for HTTP responses.

enum error-handling api

Python

from enum import Enum

class APIErrorCode(Enum):
    SUCCESS = 0
    BAD_REQUEST = 400
    UNAUTHORIZED = 401
    FORBIDDEN = 403
    NOT_FOUND = 404
    CONFLICT = 409
    INTERNAL_ERROR = 500


def describe_error(code):
    descriptions = {
        APIErrorCode.SUCCESS: "Request completed successfully",
        APIE…

12 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…

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…

14 0 Open

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