Sometimes when building trackers, you need third party libraries.
These can often be installed using pip install. If you are using virtual environments this is low risk as it is available only to programs using your virtual environment.
However if you are using a shared python environment (e.g. on a hosting provider) where you can't use pip, you can install a python library in your tracker's lib subdirectory. If you don't have a lib subdirectory you can create it with mkdir lib. Then you can download the library from the Python package inventory or from another source.
The tracker lib directory is placed at the front of Python's sys.path when your tracker is running. For example:
If you downloaded onetimepass, copying the onetimepass directory into lib would make it available for use when implementing OneTimePasswords. Another example is given on TestPasswordComplexity where you can copy the zxcvbn directory under lib to use the third party library.