Many python users have a lot of scripts.
They use some words for classes or some functions.
Sometime is hard to remember where it's this scripts.
So the easy way to do that is to find the script where is some words.
For example you need to find this : word_in_your_script
To do that just see next linux command:
$ find ~/ -type f -iname "*.py" -exec grep -l 'word_in_your_script' {} \;