Requests to delete a node by the given key.

def delete(self, key, dir=False, recursive=False,
               prev_value=None, prev_index=None, timeout=None):
        """Requests to delete a node by the given key."""
        url = self.make_key_url(key)
        params = self.build_args({
            'dir': (bool, dir or None),
            'recursive': (bool, recursive or None),
            'prevValue': (six.text_type, prev_value),
            'prevIndex': (int, prev_index),
        })
        try:
            res = self.session.delete(url, params=params, timeout=timeout)
        except:
            self.erred()
        return self.wrap_response(res)