code template for Python 3

python3.py

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


"""
code template for Python 3
__author__ = 'Your Name (your.email@address.info)'
__copyright__ = 'No copyright, just copyleft!'
"""


###########
# imports #
###########
import argparse
import logging
import sys


#########
# types #
#########
class MyClass(object):
    """
    base class is always object.
    only class names are pascal case and all the others are snake case. there is no camel case.
    """

    def __init__(self):
        super().__init__()    # call super class's initialization function
        self.your_member = 'members are lower snake cases'
        self._my_member = 'private members start with underscore'

    def your_method(self, first_arg: int, second_arg: str):
        """
        methods are lower snake cases
        Google style docstrings: http://www.sphinx-doc.org/en/master/ext/example_google.html
        Args:
            first_arg (int):  function arguments are lower snake cases
            second_arg (str):  do not align arguments vertically with spaces.
                               it causes unnecessary code changes when arguments are added.
        Returns:
            value1
            value2
        """
        self._my_method()
        return first_arg, second_arg

    def _my_method(self):
        """
        private methods start with underscore
        """
        pass

    @classmethod
    def everybodys_method(cls):
        """
        class methods are same as instance methods
        """
        pass


#############
# constants #
#############
YOUR_CONSTANT = 'constants are upper snake cases'
_MY_CONSTANT = 'private constants start with underscore'


#############
# functions #
#############
def run(args):    # pylint: disable=unused-argument
    """
    actual function which is doing some task
    Args:
        args:  program arguments
    """
    for line_num, line in enumerate(sys.stdin, start=1):
        line = line.rstrip('\r\n')
        logging.debug('%d: %s', line_num, line)
        print(line)


########
# main #
########
def main():
    """
    main function processes only argument parsing
    """
    parser = argparse.ArgumentParser(description='cat')
    parser.add_argument('--input', help='input file <default: stdin>', metavar='FILE')
    parser.add_argument('--output', help='output file <default: stdout>', metavar='FILE')
    parser.add_argument('--debug', help='enable debug', action='store_true')
    args = parser.parse_args()

    if args.input:
        sys.stdin = open(args.input, 'r', encoding='UTF-8')
    if args.output:
        sys.stdout = open(args.output, 'w', encoding='UTF-8')
    if args.debug:
        logging.basicConfig(level=logging.DEBUG)
    else:
        logging.basicConfig(level=logging.INFO)

    run(args)


if __name__ == '__main__':
    main()