If got this code with the 20second sleep statement. And I am not really sure if it is a good idea to have it ...

def start_instance(self):
instance=self.ec2.Instance(self.iId)
instance.start()
while instance.state['Name'] != 'running':
sleep(5)
instance=self.ec2.Instance(self.iId)
sleep(20) #Let's sleep another 20 for the server to be really up
return instance.state

Can I have some advice regarding best practices?