demandimport: fix compatibility with meta path finders w/o find_spec() method Meta path finders got a find_spec() method in Python version 3.4. The sys.meta_path documentation says that the deprecated find_module() method is used as a fallback. Setuptool’s VendorImporter still doesn’t have the find_spec() method, which resulted in a crash e.g. within a virtual environment. For reference, I opened an issue for that: https://github.com/pypa/setuptools/issues/2104. An alternative implementation would have been to implement a wrapper for find_module() itself and raise an AttributeError when accessing find_spec() if the wrapped finder doesn’t have it.