Python如何定义接口和抽象类

from abc import ABCMeta, abstractmethod

class IStream(metaclass=ABCMeta):
  @abstractmethod
  def read(self, maxbytes=-1):
    pass

  @abstractmethod
  def write(self, data):
    pass

a = IStream() # TypeError: Can't instantiate abstract class
        # IStream with abstract methods read, write

class SocketStream(IStream):
  def read(self, maxbytes=-1):
    pass

  def write(self, data):
    pass

def serialize(obj, stream):
  if not isinstance(stream, IStream):
    raise TypeError('Expected an IStream')
  pass

import io

# Register the built-in I/O classes as supporting our interface
IStream.register(io.IOBase)

# Open a normal file and type check
f = open('foo.txt')
isinstance(f, IStream) # Returns True

class A(metaclass=ABCMeta):
  @property
  @abstractmethod
  def name(self):
    pass

  @name.setter
  @abstractmethod
  def name(self, value):
    pass

  @classmethod
  @abstractmethod
  def method1(cls):
    pass

  @staticmethod
  @abstractmethod
  def method2():
    pass

import collections

# Check if x is a sequence
if isinstance(x, collections.Sequence):
...

# Check if x is iterable
if isinstance(x, collections.Iterable):
...

# Check if x has a size
if isinstance(x, collections.Sized):
...

# Check if x is a mapping
if isinstance(x, collections.Mapping):