code: def distribution_files(self) -> Iterator[str]:
          
          # This is verbatim from flake8
          if self.distribution.packages:
              package_dirs = self.distribution.package_dir or {}
              for package in self.distribution.packages:
                  pkg_dir = package
                  if package in package_dirs:
                      pkg_dir = package_dirs[package]
                  elif '' in package_dirs:
                      pkg_dir = package_dirs[''] + os.path.sep + pkg_dir
                  yield pkg_dir.replace('.', os.path.sep)
  
          if self.distribution.py_modules:
              for filename in self.distribution.py_modules:
                  yield "%s.py" % filename
          # Don't miss the setup.py file itself
          yield "setup.py"
docs: Find distribution packages.