diff --git a/src/core_ffi/python_ffi/binder/group.cc b/src/core_ffi/python_ffi/binder/group.cc
index 24d239a..568b91b 100644
--- a/src/core_ffi/python_ffi/binder/group.cc
+++ b/src/core_ffi/python_ffi/binder/group.cc
@@ -1,3 +1,5 @@
+#include <pybind11/stl.h>
+
 #include "binder.h"
 
 #include "py_ffi/cases.h"
diff --git a/src/core_ffi/python_ffi/binder/group_union.cc b/src/core_ffi/python_ffi/binder/group_union.cc
index 5e739c2..d7629c9 100644
--- a/src/core_ffi/python_ffi/binder/group_union.cc
+++ b/src/core_ffi/python_ffi/binder/group_union.cc
@@ -1,3 +1,5 @@
+#include <pybind11/stl.h>
+
 #include "binder.h"
 
 #include "py_ffi/cases.h"
diff --git a/src/core_ffi/python_ffi/binder/klsk_code.cc b/src/core_ffi/python_ffi/binder/klsk_code.cc
index f8599bc..1e6065f 100644
--- a/src/core_ffi/python_ffi/binder/klsk_code.cc
+++ b/src/core_ffi/python_ffi/binder/klsk_code.cc
@@ -54,6 +54,13 @@ static void bind_layout(const py::module_ &mod) {
         .def("__int__", &PyLayout::value)
         .def("__repr__", &PyLayout::repr)
 
+        .def("__copy__", [](const PyLayout &self) {
+            return PyLayout(self);
+        })
+        .def("__deepcopy__", [](const PyLayout &self, py::dict) {
+            return PyLayout(self);
+        }, py::arg("memo"))
+
         .def("next_cases", &PyLayout::next_cases)
         .def("dump_seq", &PyLayout::dump_seq)
         // TODO: add fast_cal / fast_cal_multi / ...