不同的并发范式包括多线程、协程、异步和并行等。下面给出几种范式的代码示例，以帮助理解它们之间的区别。

多线程示例：

import threading

def print_numbers():
    for i in range(5):
        print(threading.current_thread().name, i)

t1 = threading.Thread(target=print_numbers, name='Thread 1')
t2 = threading.Thread(target=print_numbers, name='Thread 2')

t1.start()
t2.start()

t1.join()
t2.join()

协程示例：

def printing():
    for i in range(5):
        print('Coroutine', i)
        yield

c = printing()
next(c)
next(c)
next(c)
next(c)
next(c)

异步示例：

import asyncio

async def print_numbers():
    for i in range(5):
        print(i)
        await asyncio.sleep(1)

async def main():
    await asyncio.gather(print_numbers(), print_numbers())

asyncio.run(main())

并行示例：

from concurrent.futures import ProcessPoolExecutor, as_completed

def print_numbers(i):
    print(i)

with ProcessPoolExecutor() as executor:
    futures = [executor.submit(print_numbers, i) for i in range(5)]

    for future in as_completed(futures):
        pass