Returns the struct with the given name, or raises RpcException if no struct matches

def struct(self, struct_name):
        """
        Returns the struct with the given name, or raises RpcException if no struct matches
        """
        if self.structs.has_key(struct_name):
            return self.structs[struct_name]
        else:
            raise RpcException(ERR_INVALID_PARAMS, "Unknown struct: '%s'", struct_name)