We will use the term "inline comment" to refer to all comments that are meant for maintenance coders and will never be visible to anyone not reading the source code.
Inline comments start with a #
sign and continue up to the end of the line. They may not occur within a string literal. No characters within an inline comment are interpreted.
Python does not support block comments. Rumors to the effect that triple double-quotes (" " ") can be used to comment out multiple lines are to be disbelieved. While that will often work, what actually happens is that Python looks at the included lines as one multiline string. As a string, the included lines are not interpreted. A string literal is created instead. As this new literal is not assigned to a variable, it is immediately garbage-collected.
In addition to this strange behavior, triple double-quotes are used for docstrings. Using them for both purposes can be confusing, which is what we set out to avoid in the first place.