import requests
import hashlib

KEYS = {
    'public': '3bc48ca2dd73e6eb8aa42a458ad3dabb',
    'private': '40fac5841bd7d67740e61ff36cd166ad',
}


def get_sorted_keys(obj):
    """
    sort object keys alphabetically

    :param dict obj: dict object
    :return: alphabetically sorted array of obj keys
    """
    return sorted(list(obj.keys()))


def generate_data_string(obj, private_key):
    """
    generate string for api call from object and private key
    :param dict obj: dict object with interesting fields like begin_date
    :param str private_key: string with private key
    :return str: string for sign
    example:
    generate_data_string({atest1: '1', btest2: '2'}, blabla)
    =>
    atest1=1btest2=2blabla
    """
    sorted_obj_keys = get_sorted_keys(obj)
    string = ''
    for key in sorted_obj_keys:
        string += '{key}={value}'.format(key=key, value=obj[key])
    return string + private_key


def generate_md5(string):
    """
    generate md5 string for sign
    :param str string:
    :return: md5 string
    """
    return hashlib.md5(string.encode('utf-8')).hexdigest()


data = {
    'begin_date': '2017-11-16',
    'end_date': '2017-12-20',
}

print(generate_data_string(data, KEYS['private']))
# => begin_date=2017-11-16end_date=2017-12-2040fac5841bd7d67740e61ff36cd166ad
print(generate_md5(generate_data_string(data, KEYS['private'])))
# => a6c37ca03653e11bc98f8520fdae91b8

sign = generate_md5(generate_data_string(data, KEYS['private']))
data['sign'] = sign

print(data)
# => {'end_date': '2017-12-20', 'sign': 'a6c37ca03653e11bc98f8520fdae91b8', 'begin_date': '2017-11-16'}

req_url = 'https://realtycalendar.ru/api/v1/bookings/{}'.format(KEYS['public'])
print(req_url)
# => https://realtycalendar.ru/api/v1/bookings/3bc48ca2dd73e6eb8aa42a458ad3dabb

response = requests.post(url=req_url, data=data)

# Информация о запросе
print(response.request.body, response.request.url, response.request.method)
# => sign=a6c37ca03653e11bc98f8520fdae91b8&begin_date=2017-11-16&end_date=2017-12-20 https://realtycalendar.ru/api/v1/bookings/3bc48ca2dd73e6eb8aa42a458ad3dabb POST



print(response.status_code)
# => 404
# в коде ответа значится 404 'Страница не найдена'