'Authorize an httplib2.Http instance with these credentials.
The modified http.request method will add authentication headers to
each request and will refresh access_tokens when a 401 is received on a
request. In addition the http.request method has a credentials
property, http.request.credentials, which is the Credentials object
that authorized it.
Args:
http: An instance of ``httplib2.Http`` or something that acts
like it.
Returns:
A modified instance of http that was passed in.
Example::
h = httplib2.Http()
h = credentials.authorize(h)
You can\'t create a new OAuth subclass of httplib2.Authentication
because it never gets passed the absolute URI, which is needed for
signing. So instead we have to overload \'request\' with a closure
that adds in the Authorization header and then calls the original
version of \'request()\'.'

def authorize(self, http):

    transport.wrap_http_for_auth(self, http)
    return http
