We needed to implement a callback from c++. This callback is passed as a std::function to a method.
I found an answer from @Flexo in StackOverflow that provides a std_function.i to solve this problem:

I’m currently exploring SWIG to facilitate wrapping around three C++ header files (file1.h, file2.h, file3.h). I’ve included these header files in my SWIG interface file using the %include directive.