def on_getheaders(self, conn, message):
    response = self.block_store.headers_for(message.locator, message.hashstop)
    if (response is not None):
        conn.send_message(response)
def on_getheaders(self, conn, message):
    response = self.block_store.headers_for(message.locator, message.hashstop)
    if (response is not None):
        conn.send_message(response)