我的Python应用程序包含许多抽象类和实现。例如：import abc

import datetime

class MessageDisplay(object):

__metaclass__ = abc.ABCMeta

@abc.abstractproperty

def display(self, message):

pass

class FriendlyMessageDisplay(MessageDisplay):

def greet(self):

hour = datetime.datetime.now().timetuple().tm_hour

if hour < 7:

raise Exception("Cannot greet while asleep.")

elif hour < 12:

self.display("Good morning!")

elif hour < 18:

self.display("Good afternoon!")

elif hour < 20:

self.display("Good evening!")

else:

self.display("Good night.")

class FriendlyMessagePrinter(FriendlyMessageDisplay):

def display(self, message):

print(message)

FriendlyMessagePrinter是一个具体的类，我们可以使用它。。。FriendlyMessagePrinter().greet()Good night.

…但是MessageDisplay和FriendlyMessageDisplay是抽象类，试图实例化一个类将导致错误：TypeError: Can't instantiate abstract class MessageDisplay with abstract methods say

如何检查给定的类对象是否是(不可实例化的)抽象类？