Project Packaging & Metadata

• setup.py: Used to package and distribute Python projects.
• Build tool: Use setuptools to define package name, version, dependencies, etc.
• Semantic Versioning: Follows MAJOR.MINOR.PATCH, e.g., 1.0.0.
• Special package attributes:

Logging

• Import logger directly: from logging import Logger
• Common methods of logging.Logger instance: debug(), info(), warning(), error(), critical()
• Logger setup best practices (setup_logging)
• Create a logs directory
• Define a formatter
• Get or create a named logger
• Set logger.propagate = False to stop duplicate logs
• Add file & console handlers only if not already added

Retry Logic with tenacity, @retry it’s a decorator

Context Manager Protocol

To create a custom context manager (used with with), implement:

• __init__(self, ...): Constructor (e.g., accept config path)
• __enter__(self): Called at start of with block
• __exit__(self, exc_type, exc_val, exc_tb): Called at the end (even on error)

with DatabaseConnection("config.yml") as conn:
    df = pd.read_sql("SELECT * FROM table", conn.engine)

A hash function is a function that takes an input (called a key) and produces a fixed-size string of bytes (usually a number), which is called a hash. maps data of arbitrary size to data of fixed size — often a numeric value (e.g. int or hex). In Python, the built-in hash() function is not consistent across sessions for security reasons (hash randomization). For persistent hashes, use hashlib.

Add concurrent, safety thread considerations: first we can Use Locks or Synchronization

import threading

class Spot:
    def __init__(self):
        self.lock = threading.Lock()
        self.is_occupied = False

    def assign_vehicle(self):
        with self.lock:
            if not self.is_occupied:
                self.is_occupied = True
                return True
            return False

Or use Thread-Safe Data Structures: queue.Queue; threading.Lock; multiprocessing.Value

Consider Message Queues (Advanced)

Decouple entry/exit panels from the core system:

Panel sends “assign vehicle” or “free spot” event to a queue; A central service processes events serially.

Without lock vs. with lock

import threading

counter = 0
lock = threading.Lock()

def increment():
    global counter
    for _ in range(10000):
        with lock:  # only one thread can enter this block at a time
            counter += 1

thundermethod:

Note the index operation is also a thundermethod

Context manager has enter and exit thundermethod.

Iterator has iter and next thundermethod.