api_task.py

from urllib.request import urlopen
from json import loads
from _datetime import datetime
from itertools import groupby


url = 'https://ru.wikipedia.org/w/api.php?action=query&format=json&prop=revisions&rvlimit=500&titles=%D0%93%D1%80%D0%B0%D0%B4%D1%81%D0%BA%D0%B8%D0%B9,_%D0%90%D0%BB%D0%B5%D0%BA%D1%81%D0%B0%D0%BD%D0%B4%D1%80_%D0%91%D0%BE%D1%80%D0%B8%D1%81%D0%BE%D0%B2%D0%B8%D1%87'
data = loads(urlopen(url).read().decode('utf8'))
changes = data['query']['pages']['183903']['revisions']


def get_time(change):
    return datetime.strptime(change['timestamp'], '%Y-%m-%dT%H:%M:%SZ').date()


for key, items in groupby(changes, key=get_time):
    count = 0
    for item in items:
        count += 1
    print(key, count)