Unable to conversion in Expected<unique_ptr<Module>> to Module

Hi, I am new to llvm , writing the program “main.cpp” of https://github.com/davidar/lljvm/blob/master/backend/main.cpp.

I stuck at the error while executing the command : “pm.run(m)”

error: no matching function for call to ‘llvm::legacy::PassManager::run(llvm::Expected<std::unique_ptrllvm::Module >&)

Here is my source code: