docs: def _build_exclusion_list(exclude):
      """Build file names list of modules to exclude from exception handling."""
      mod_files = []
      if exclude:
          for mod in exclude:
              mdir = None
              mod_file = None
              for token in mod.split("."):
                  try:
                      mfile, mdir, _ = imp.find_module(token, mdir and [mdir])
                      if mfile:
                          mod_file = mfile.name
                          mfile.close()
                  except ImportError:
                      msg = "Source for module {mod_name} could not be found"
                      raise ValueError(msg.format(mod_name=mod))
              if mod_file:
                  mod_files.append(mod_file.replace(".pyc", ".py"))
      return mod_files