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How to Print an Exception Chain in Python for Debugging
A helper that walks an exception's __cause__ and __context__ chain, printing each level with indentation to make debugging nested errors clearer.
import sys
import traceback
def pretty_exception_chain(exc):
"""Print the full exception chain with cause/context details."""
chain = []
current = exc
seen = set()
while current is not None and id(current) not in seen:
seen.add(id(current))
chain.append(current)
curren…How to Build a Data Helper for LLM Prompts in Python
A beginner-friendly helper class that flattens nested dictionaries, formats prompt templates, and safely parses JSON for AI/LLM pipelines.
import json
from typing import Any, Dict, List, Optional
class DataHelper:
"""Simple helper class for working with data in AI/LLM pipelines."""
def __init__(self, data: Optional[Dict[str, Any]] = None) -> None:
self.data = data or {}
def flatten(self, prefix: str = "") -> Dict[str, Any]…How to Mock Git Cherry-Pick in Python for Tests
Mock the `repo.git.cherry_pick` method with `unittest.mock` to test a Git cherry-pick helper without a real repository.
from unittest.mock import patch, MagicMock
class GitCherryPicker:
def __init__(self):
self.applied_commits = []
def cherry_pick(self, commit_hash, repo):
try:
result = repo.git.cherry_pick(commit_hash)
self.applied_commits.append(commit_hash)
return f"A…How to Compare Execution Speed Between Python Functions
Measure and compare the average execution time of multiple Python functions using a reusable benchmark helper with time.perf_counter.
import time
import random
def method_a(values):
"""Sort using built-in sorted."""
return sorted(values)
def method_b(values):
"""Sort using list's sort method."""
values_copy = values[:]
values_copy.sort()
return values_copy
def method_c(values):
"""Sort manually using bubble sort (slow,…How to Validate Data in Python with Typing Hints
Build a runtime validation helper that checks values against Python type hints like Optional, list, and basic types.
from typing import Any, Optional, Union, TypeVar, get_origin, get_args
T = TypeVar("T")
def validate(value: Any, expected_type: type) -> Optional[str]:
"""Returns an error message if value doesn't match expected_type, else None."""
# Handle Optional[...] types
origin = get_origin(expected_type)
if or…How to Validate and Cache Data with Redis in Python
A beginner-friendly helper that validates email, phone, and age data and caches validated entries in Redis for 5 minutes.
import redis
import json
from functools import wraps
class DataValidator:
def __init__(self, host="localhost", port=6379, db=0):
self.cache = redis.Redis(host=host, port=port, db=db)
self.validators = {
"email": lambda v: "@" in v and "." in v.split("@")[-1],
"phone": lambd…How to Create a Mock ONNX Model in Python
Build and export a minimal mock ONNX model with a Reshape and Gemm layer using the onnx helper API.
import onnx
import numpy as np
from onnx import helper, TensorProto
def create_mock_model():
# Define input and output tensors
input_tensor = helper.make_tensor_value_info('input', TensorProto.FLOAT, [1, 3, 224, 224])
output_tensor = helper.make_tensor_value_info('output', TensorProto.FLOAT, [1, 10])
…Database Helper in Python with SQLite Scaling Optimization
Build a beginner-friendly SQLite database helper class with WAL, indexed queries, and efficient batch inserts for scaling.
import sqlite3
from contextlib import contextmanager
class DatabaseHelper:
"""Beginner-friendly helper for SQLite database operations with scaling tips."""
def __init__(self, db_path):
self.db_path = db_path
@contextmanager
def connection(self):
"""Context manager for automatic comm…How to Sign and Verify with Ed25519 in Python
A minimal Ed25519 sign-and-verify helper that generates a key pair, signs a message, and checks the signature with the cryptography library.
import hashlib
from cryptography.hazmat.primitives.asymmetric import ed25519
from cryptography.hazmat.primitives import serialization
def sign_verify_mock(
message: bytes,
private_key: ed25519.Ed25519PrivateKey,
public_key: ed25519.Ed25519PublicKey
) -> tuple[bool, bytes]:
signature = private_key.sign…Browse by section
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