__init__.py 文件源码

def is_package(module_name):
    """
    Check if a Python module is really a module or is a package containing
    other modules.

    :param module_name: Module name to check.
    :return: True if module is a package else otherwise.
    """
    # This way determines if module is a package without importing the module.
    try:
        loader = pkgutil.find_loader(module_name)
    except Exception:
        # When it fails to find a module loader then it points probably to a class
        # or function and module is not a package. Just return False.
        return False
    else:
        if loader:
            # A package must have a __path__ attribute.
            return loader.is_package(module_name)
        else:
            # In case of None - modules is probably not a package.
            return False