def save_object(self, obj):
        r"""
        Saves the given object to a file

        Parameters
        ----------
        obj : OpenPNM object
            The file to be saved.  Depending on the object type, the file
            extension will be one of 'net', 'geo', 'phase', 'phys' or 'alg'.
        """
        if not isinstance(obj, list):
            obj = [obj]
        for item in obj:
            filename = item.name + '.' + item.settings['prefix']
            with open(filename, 'wb') as f:
                pickle.dump({item.name: item}, f)