def authGSSClientStep(context, challenge, **kwargs):
    """
    Processes a single GSSAPI client-side step using the supplied server data.

    @param context: the context object returned from authGSSClientInit.
    @param challenge: a string containing the base64-encoded server data (which may be empty
        for the first step).
    @param channel_bindings: Optional channel bindings to bind onto the auth request. This
        struct can be built using the channelBindings function and it not specified, this process
        will pass along GSS_C_NO_CHANNEL_BINDINGS as a default
    @return: a result code (see above).
    """
