Does the API-style path (directory) actually exist?

        Parameters
        ----------
        path : string
            The path to check. This is an API path (`/` separated,
            relative to base notebook-dir).

        Returns
        -------
        exists : bool
            Whether the path is indeed a directory.

def path_exists(self, path):
        """Does the API-style path (directory) actually exist?

        Parameters
        ----------
        path : string
            The path to check. This is an API path (`/` separated,
            relative to base notebook-dir).

        Returns
        -------
        exists : bool
            Whether the path is indeed a directory.
        """

        path = path.strip('/')
        if path != '':
            spec = {'path': path}
            count = self._connect_collection(self.notebook_collection).find(spec).count()
        else:
            count = 1
        return count > 0