python async callback code example

Example 1: python async await

import asyncio

async def print_B(): #Simple async def
    print("B")

async def main_def():
    print("A")
    await asyncio.gather(print_B())
    print("C")
asyncio.run(main_def())

# The function you wait for must include async
# The function you use await must include async
# The function you use await must run by asyncio.run(THE_FUNC())

Example 2: python async await

import asyncio
from PIL import Image
import urllib.request as urllib2

async def getPic(): #Proof of async def
    pic = Image.open(urllib2.urlopen("https://c.files.bbci.co.uk/E9DF/production/_96317895_gettyimages-164067218.jpg"))
    return pic

async def main_def():
    print("A")
    print("Must await before get pic0...")
    pic0 = await asyncio.gather(getPic())
    print(pic0)
asyncio.run(main_def())