How to provide bindings to cpp objects through cython?

I want to add hash functionality to unordered_map but having trouble understanding the semantics in cython

I have the following definition

cdef extern from * using namespace "std":
    """
    struct pair_hash {
        template <class T1, class T2>
        std::size_t operator () (const std::pair<T1,T2> &p) const {
            auto h1 = std::hash<T1>{}(p.first);
            auto h2 = std::hash<T2>{}(p.second);
        return h1 ^ h2;  
        }
    };
    """
    cdef cppclass pair_hash:
       pass

   cdef cppclass unordered_map[T, U, H]:
       pass

I have browsed around the unordered_map code to see how bindings is done.

My question is how to approach these bindings in general? So far I have deduced that mapping would involve

• Correct name space
• tell cython what the object is through cppclass
• provide method names to be bound

Here, however I need to bind a template and I am a little lost on how to approach this.