Will be executed in the first time someone calls classes_*()

def __setup():
    """Will be executed in the first time someone calls classes_*() """
    global __collaborators, __flag_first

    import f311

    __flag_first = False
    for pkgname in f311.COLLABORATORS_C:
        try:
            pkg = importlib.import_module(pkgname)
            a99.get_python_logger().info("Imported collaborator package '{}'".format(pkgname))

            try:
                if hasattr(pkg, "_setup_filetypes"):
                    pkg._setup_filetypes()
                else:
                    _collect_classes(pkg)

                __collaborators[pkgname] = pkg
            except:
                a99.get_python_logger().exception(
                    "Actually, package '{}' gave error".format(pkgname))
                raise
        except:
            a99.get_python_logger().warning("Failed to import package '{}".format(pkgname))