These methods are used to configure rules after they are loaded.
They should all be of the form
setup/REPO_setup.bzl:
load("@REPO//:workspace.bzl", "some_setup_method")
def REPO_setup():
some_setup_method()
Where:
REPO
is the name of the repositorysome_setup_method
is the name the repository chose for their setup. We give it the name REPO_setup to provide a uniform pattern.