Python coding convention

tl;dr

• Always follow both PEP 20 - The Zen of Python and PEP 8 - Style Guide for Python Code (example).
• PEP 20 supersedes PEP 8.
• This guide supersedes PEP 20.

Line Length

Strictly less than or equal to 79 characters, unless any of these applies:

• it is impossible to break the line up to below 79 characters
• it looks uglier than before you trim it down to 79 characters
• line length includes spaces.

Tabs and spaces

• no tab characters of any kind shall be found in our code.
• no trailing spaces of any kind shall be found in our code.
• indentation: 4 hard spaces.

Class Names

• CamelCase

Property Names

• prop_name

Variable Names

• var_name
• at least three meaningful characters, unless it is a variable used for looping, itself unused in the loop. In which case, use _.

Docstrings / Comments

• use PEP 257.
• docstrings must be meaningful.
• there is (hardly ever) too many comments - as long as they are meaningful, updated, and don't repeat themselves

Trailing commas

Always for dictionaries, and never for tuples