Style

Indentation and Spacing / Horizontal Spacing

Always use 4 space tabbing. (i.e. not \t character)
Keep spacing around operators

script.python

sum = a + b  # goodsum=a+b      # bad

Limit line length to be < 80 characters

Use blank lines to separate logical blocks

script.python

def foo():  validation_user_input()  process_authentication()  initialize()  other_thing()

It is preferred to use vertical separators sparingly, having single lines of code isolated vertically is not preferred.

Always use trailing commas (results in consistent git merging behavior)

script.python

data = {    "key": 5,    "key2": 4, # <-- this one}

For quotations always use double quotes: "
Inner single quotes ' are acceptable

script.python

"This is a string" # ok"This is a 'string'" # inner ' is acceptabledict["key"] # even in dictionary key accessing " is used