Return a serializable form of the config instance

def serialize(self):
        '''
        Return a serializable form of the config instance
        '''
        serialized = {'type': self.__type__}
        for argname in self._attributes:
            if argname == 'required':
                # This is handled elsewhere
                continue
            argvalue = self._get_argname_value(argname)
            if argvalue is not None:
                if argvalue is Null:
                    argvalue = None
                # None values are not meant to be included in the
                # serialization, since this is not None...
                if self.__serialize_attr_aliases__ and argname in self.__serialize_attr_aliases__:
                    argname = self.__serialize_attr_aliases__[argname]
                serialized[argname] = argvalue
        return serialized