def get_resource_inst(self, path, environ):
raise NotImplementedError<EOL>
Return a _DAVResource object for path.

        Should be called only once per request and resource::

            res = provider.get_resource_inst(path, environ)
            if res and not res.is_collection:
                print(res.get_content_type())

        If <path> does not exist, None is returned.
        <environ> may be used by the provider to implement per-request caching.

        See _DAVResource for details.

        This method MUST be implemented.