Add a matching _unwrap_grpc_arg

src/python/grpcio/grpc/_cython/_cygrpc/arguments.pxd.pxi

@@ -25,6 +25,9 @@ cdef int _compare_pointer(void* first_pointer, void* second_pointer)
 cdef tuple _wrap_grpc_arg(grpc_arg arg)
 
 
+cdef grpc_arg _unwrap_grpc_arg(tuple wrapped_arg)
+
+
 cdef class _ArgumentProcessor:
 
   cdef grpc_arg c_argument

src/python/grpcio/grpc/_cython/_cygrpc/arguments.pyx.pxi

@@ -40,12 +40,16 @@ cdef class _GrpcArgWrapper:
 
 
 cdef tuple _wrap_grpc_arg(grpc_arg arg):
-
   wrapped = _GrpcArgWrapper()
   wrapped.arg = arg
   return ("grpc.python._cygrpc._GrpcArgWrapper", wrapped)
 
 
+cdef grpc_arg _unwrap_grpc_arg(tuple wrapped_arg):
+  cdef _GrpcArgWrapper wrapped = wrapped_arg[1]
+  return wrapped.arg
+
+
 cdef class _ArgumentProcessor:
 
   cdef void c(self, argument, grpc_arg_pointer_vtable *vtable, references):