def custom_build_class_rule(self, opname, i, token, tokens, customize):
        '''
        # Should the first rule be somehow folded into the 2nd one?
        build_class ::= LOAD_BUILD_CLASS mkfunc
                        LOAD_CLASSNAME {expr}^n-1 CALL_FUNCTION_n
                        LOAD_CONST CALL_FUNCTION_n
        build_class ::= LOAD_BUILD_CLASS mkfunc
                        expr
                        call
                        CALL_FUNCTION_3
         '''
        # FIXME: I bet this can be simplified
        # look for next MAKE_FUNCTION
        for i in range(i+1, len(tokens)):
            if tokens[i].kind.startswith('MAKE_FUNCTION'):
                break
            elif tokens[i].kind.startswith('MAKE_CLOSURE'):
                break
            pass
        assert i < len(tokens), "build_class needs to find MAKE_FUNCTION or MAKE_CLOSURE"
        assert tokens[i+1].kind == 'LOAD_CONST', \
          "build_class expecting CONST after MAKE_FUNCTION/MAKE_CLOSURE"
        call_fn_tok = None
        for i in range(i, len(tokens)):
            if tokens[i].kind.startswith('CALL_FUNCTION'):
                call_fn_tok = tokens[i]
                break
        if not call_fn_tok:
            raise RuntimeError("build_class custom rule for %s needs to find CALL_FUNCTION"
                               % opname)


        # customize build_class rule
        # FIXME: What's the deal with the two rules? Different Python versions?
        # Different situations? Note that the above rule is based on the CALL_FUNCTION
        # token found, while this one doesn't.
        if self.version < 3.6:
            call_function = self.call_fn_name(call_fn_tok)
            args_pos, args_kw = self.get_pos_kw(call_fn_tok)
            rule = ("build_class ::= LOAD_BUILD_CLASS mkfunc %s"
                        "%s" % (('expr ' * (args_pos - 1) + ('kwarg ' * args_kw)),
                                    call_function))
        else:
            # 3.6+ handling
            call_function = call_fn_tok.kind
            if call_function.startswith("CALL_FUNCTION_KW"):
                self.addRule("classdef ::= build_class_kw store", nop_func)
                rule = ("build_class_kw ::= LOAD_BUILD_CLASS mkfunc %sLOAD_CONST %s"
                        % ('expr ' * (call_fn_tok.attr - 1), call_function))
            else:
                call_function = self.call_fn_name(call_fn_tok)
                rule = ("build_class ::= LOAD_BUILD_CLASS mkfunc %s%s"
                         % ('expr ' * (call_fn_tok.attr - 1), call_function))
        self.addRule(rule, nop_func)
        return