POST JSON with Python3 urllib

postdata.py

# Public domain

from urllib import request

def post_data(url, data, headers={'Content-Type':'application/json'}):
    """
    POST data string to `url`, return page and headers
    """
    # if data is not in bytes, convert to it to utf-8 bytes
    bindata = data if type(data) == bytes else data.encode('utf-8')
    # need Request to pass headers
    req = request.Request(url, bindata, headers)
    resp = request.urlopen(req)
    return resp.read(), resp.getheaders()