Add docstring.
Add docstring.

solvcon/solvcon,solvcon/solvcon,yungyuc/solvcon,yungyuc/solvcon,solvcon/solvcon,solvcon/solvcon,yungyuc/solvcon,solvcon/solvcon,yungyuc/solvcon,solvcon/solvcon,yungyuc/solvcon,yungyuc/solvcon