'Convert any path to an absolute path.
This method returns the absolute path as a string, or a Deferred
that returns the same.
@type path: L{bytes}
@param path: the path to convert as a string.'

def realPath(self, path):

    d = self._sendRequest(FXP_REALPATH, NS(path))
    return d.addCallback(self._cbRealPath)
