Python style guide example

example.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

# The above two lines specify two things. The order must always be the same if both are used.
# The first line is a shebang, used by Unix-like systems to determine how to run a file.
# The second is a way to specify the encoding used by the file.

# Neither are necessary, especially the second one, since Python 3 is UTF-8 by default.

"""
Module-level docstring

This describes what the module is about.
It must be placed before any valid Python code,
otherwise it will be ignored.

See PEP-257 for the official docstring conventions.
"""

# Imports from the standard library. Note the alphabetical order.
import math
import operator
from pathlib import Path

# Imports from third-party libraries.
import numpy as np
import requests
from escapyde import FRED, FGREEN, FBLUE
from iplib3 import IPAddress

# Imports from modules defined in the project.
import my_module
from project_constants import MAX_POWER_LIMIT

# Constants used in the project. Order either alphabetical or otherwise logical.

DESKTOP = Path.home() / 'Desktop'
ROOT_DIR = Path(__file__).parent
DATA_DIR = ROOT_DIR / 'data'

MAX_CHEESE_WEIGHT = 420  # kg

# Classes and functions; either can be first, there's no clear consensus.
# Just don't mix them. Order logically, then alphabetically.

def age_total(people):
    """Calculate and return the total age of given people."""
    
    total = 0
    for person in people:
        total = my_module.add(total, person.age)
    return total


class Person:
    def __init__(self, name, age=0):
        self.name = name
        self.age = age
        
# If you want to run the module as a script, add the following to the bottom.
# Ideally you'd also have a main function and just call it there. That way you
# can run everything even if you import the module, should you wish.

if __name__ == '__main__':
    people = [Person('test') for _ in range(10)]
    print(age_total(people))

my_module.py

"""
Lorem Ipsum

Dolor sit amet.
"""

def add(a, b):
    return a + b

project_constants.py

"""
Lorem Ipsum

Dolor sit amet.
"""

MAX_POWER_LIMIT = 255