Error converting miasm IR to LLVM

I am trying to lift a binary into LLVM IR. I combined [Full Disasm](https://github.com/cea-sec/miasm/blob/master/example/disasm/full.py) with [Export to LLVM](https://github.com/cea-sec/miasm/blob/master/example/expression/export_llvm.py) scripts and used modeled call lifter. I got the following IR:  But when invoking `func.from_ircfc`, it errors with the following error: `NotImplementedError: Unknown op: call_func_ret`  Is there any way to lift a function that contains other functions? Thank you!