The statusreasons module is accessible via the webob module.
{100: 'Continue',
101: 'Switching Protocols',
102: 'Processing',
200: 'OK',
201: 'Created',
202: 'Accepted',
203: 'Non Authoritative Information',
204: 'No Content',
205: 'Reset Content',
206: 'Partial Content',
207: 'Multi Status',
226: 'IM Used',
300: 'Multiple Choices',
301: 'Moved Permanently',
302: 'Found',
303: 'See Other',
304: 'Not Modified',
305: 'Use Proxy',
307: 'Temporary Redirect',
400: 'Bad Request',
401: 'Unauthorized',
402: 'Payment Required',
403: 'Forbidden',
404: 'Not Found',
405: 'Method Not Allowed',
406: 'Not Acceptable',
407: 'Proxy Authentication Required',
408: 'Request Timeout',
409: 'Conflict',
410: 'Gone',
411: 'Length Required',
412: 'Precondition Failed',
413: 'Request Entity Too Large',
414: 'Request URI Too Long',
415: 'Unsupported Media Type',
416: 'Requested Range Not Satisfiable',
417: 'Expectation Failed',
422: 'Unprocessable Entity',
423: 'Locked',
424: 'Failed Dependency',
426: 'Upgrade Required',
500: 'Internal Server Error',
501: 'Not Implemented',
502: 'Bad Gateway',
503: 'Service Unavailable',
504: 'Gateway Timeout',
505: 'HTTP Version Not Supported',
507: 'Insufficient Storage',
510: 'Not Extended'}
See the source for more information.