Porting Cryptsy authenticatedAPI to Python 3 - authentication

Question

I am trying to port a class I use to connect to Cryptsy's authenticated API to Python 3.3. I have managed to solve the data type issues, and am getting something that is at least getting a request from the website, but it is rejecting my authentication, this is the code, API keys are not included, for obvious reasons...:
req['method'] = method
req['nonce'] = int(time.time())
post_data = urllib.parse.urlencode(req)
sign = hmac.new(self.Secret, str.encode(post_data), hashlib.sha512).hexdigest()
headers = {
'Sign': sign,
'Key': self.APIKey
}
print('headers: ',headers)
print('post data: ',post_data)
b=urllib.parse.urlencode(headers)
print(b)
test=post_data + '&'+ b
print('test: ',test)
data=test.encode()
print('data: ',data)
ret = urllib.request.urlopen(urllib.request.Request('https://www.cryptsy.com/api', data))
q=ret.read()
w=q.decode()
e=json.loads(w)
return self.post_process(e)
And this is the response from the server:
{'error': 'Unable to Authorize Request - Check Your Post Data', 'success': '0'}
Thanks.

Answer 1

The original script had the DATA and HEADERS components for the Request, but was somehow formatted in a way that confused Python 3 into thinking the HEADERS part was a TIMEOUT argument, and throwing an error about it needing to be an INT. This sent me on a wild goose chase of trying to concatenate the DATA and HEADERS.