To test he new "this probably should be an f string" checker, they generated a list of the most popular python repositories on Github by using Github's topic search API [with this script].

With the rule:

GIVEN a string does not have an f prefix
WHEN the string contains {foo}
AND foo is in scope
THEN it’s probably missing an f prefix

And minimizing the false positive such as

• The string is later used in an str.format(…) call or str.format_map(…)
• The string is used in behave style test `@when('{user} accesses {url}.')