val = json.dumps({'offers' : [{'name': 'Принтер Panasonic HX-DC3EE White'}]}, ensure_ascii=False)
print(val)
values = val.encode('utf_8')
print(values)
url = 'https://api.partner.market.yandex.ru/v2/campaigns/%d/bids.json' % (idcom)
reg = urllib.request.Request(url, method='POST')
reg.add_header('Content-Type', 'application/json')
reg.add_header('Host', 'api.partner.market.yandex.ru')
reg.add_header('Authorization','OAuth oauth_token="", oauth_client_id="", oauth_login=""')
reg.add_data(values)
try:
        response =  urllib.request.urlopen(reg)
        json_data=response.read().decode("utf8", 'ignore')
        dataj = json.loads(json_data)
        print(dataj)
except  urllib.error.HTTPError as error:
       
        print(error.read())

{"offers": [{"name": "Принтер Panasonic HX-DC3EE White"}]}
b'{"offers": [{"name": "\xd0\x9f\xd1\x80\xd0\xb8\xd0\xbd\xd1\x82\xd0\xb5\xd1\x80 Panasonic HX-DC3EE White"}]}'

{'bids': []}