InvalidResponseError: headers must be str

[Niklas Rosencrantz]

I can log the headers and it seems that they are strings:

INFO     2011-12-31 08:43:03,286 paypal.py:143] headers: {'X-PAYPAL-REQUEST-DATA-FORMAT': 'JSON', 'X-PAYPAL-SECURITY-PASSWORD': '1324348659', 'X-PAYPAL-RESPONSE-DATA-FORMAT': 'JSON', 'X-PAYPAL-SECURITY-SIGNATURE': 'Al6H7Bq3kp4bKFht2fR-p2FlAbp3AJFKl5pFMzHpo.QKYe4Uob5YPIm.', 'X-PAYPAL-SECURITY-USERID': 'niklas_1354859649_biz_api1.eddaconsult.se', 'X-PAYPAL-DEVICE-IPADDRESS': '127.0.0.1', 'X-PAYPAL-APPLICATION-ID': 'APP-80W284485P519543T'}