diff --git a/vm/src/builtins/mod.rs b/vm/src/builtins/mod.rs
index b3fd1a317..1b3cbb7a0 100644
--- a/vm/src/builtins/mod.rs
+++ b/vm/src/builtins/mod.rs
@@ -59,7 +59,7 @@ pub(crate) mod bool_;
 pub use bool_::PyBool;
 #[path = "str.rs"]
 pub(crate) mod pystr;
-pub use pystr::{PyStr, PyStrRef};
+pub use pystr::{PyStr, PyStrInterned, PyStrRef};
 #[path = "super.rs"]
 pub(crate) mod super_;
 pub use super_::PySuper;
diff --git a/vm/src/builtins/str.rs b/vm/src/builtins/str.rs
index 151a1f1d3..0137337c1 100644
--- a/vm/src/builtins/str.rs
+++ b/vm/src/builtins/str.rs
@@ -9,6 +9,7 @@ use crate::{
     convert::{ToPyException, ToPyObject},
     format::{FormatSpec, FormatString, FromTemplate},
     function::{ArgIterable, FuncArgs, OptionalArg, OptionalOption, PyComparisonValue},
+    intern::PyInterned,
     protocol::{PyIterReturn, PyMappingMethods, PySequenceMethods},
     sequence::SequenceOp,
     sliceable::{SequenceIndex, SliceableSequenceOp},
@@ -227,7 +228,7 @@ impl IntoPyStrRef for &str {
     }
 }
 
-impl IntoPyStrRef for &'static crate::intern::PyStrInterned {
+impl IntoPyStrRef for &'static PyStrInterned {
     #[inline]
     fn into_pystr_ref(self, _vm: &VirtualMachine) -> PyRef<PyStr> {
         self.to_owned()
@@ -1741,3 +1742,27 @@ impl<'s> AnyStr<'s> for str {
         splited
     }
 }
+
+/// The unique reference of interned PyStr
+/// Always intended to be used as a static reference
+pub type PyStrInterned = PyInterned<PyStr>;
+
+impl PyStrInterned {
+    #[inline]
+    pub fn to_exact(&'static self) -> PyRefExact<PyStr> {
+        unsafe { PyRefExact::new_unchecked(self.to_owned()) }
+    }
+}
+
+impl std::fmt::Display for PyStrInterned {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        std::fmt::Display::fmt(self.as_str(), f)
+    }
+}
+
+impl AsRef<str> for PyStrInterned {
+    #[inline(always)]
+    fn as_ref(&self) -> &str {
+        self.as_str()
+    }
+}
diff --git a/vm/src/intern.rs b/vm/src/intern.rs
index 817871a19..ddef87c8e 100644
--- a/vm/src/intern.rs
+++ b/vm/src/intern.rs
@@ -1,5 +1,5 @@
 use crate::{
-    builtins::{PyStr, PyTypeRef},
+    builtins::{PyStr, PyStrInterned, PyTypeRef},
     common::lock::PyRwLock,
     convert::ToPyObject,
     AsObject, Py, PyExact, PyObject, PyObjectRef, PyPayload, PyRef, PyRefExact, VirtualMachine,
@@ -42,17 +42,16 @@ impl StringPool {
             let cache = CachedPyStrRef { inner: s };
             let inserted = zelf.inner.write().insert(cache.clone());
             if inserted {
-                let interned = unsafe { PyStrInterned::borrow_cache(&cache) };
+                let interned = unsafe { cache.as_interned_str() };
                 unsafe { interned.as_object().mark_intern() };
                 interned
             } else {
                 unsafe {
-                    PyStrInterned::borrow_cache(
-                        zelf.inner
-                            .read()
-                            .get(cache.as_ref())
-                            .expect("inserted is false"),
-                    )
+                    zelf.inner
+                        .read()
+                        .get(cache.as_ref())
+                        .expect("inserted is false")
+                        .as_interned_str()
                 }
             }
         }
@@ -68,7 +67,7 @@ impl StringPool {
         self.inner
             .read()
             .get(s.as_ref())
-            .map(|cached| unsafe { PyStrInterned::borrow_cache(cached) })
+            .map(|cached| unsafe { cached.as_interned_str() })
     }
 }
 
@@ -107,6 +106,13 @@ impl AsRef<str> for CachedPyStrRef {
 }
 
 impl CachedPyStrRef {
+    /// # Safety
+    /// the given cache must be alive while returned reference is alive
+    #[inline]
+    unsafe fn as_interned_str(&self) -> &'static PyStrInterned {
+        std::mem::transmute_copy(self)
+    }
+
     #[inline]
     fn as_str(&self) -> &str {
         self.inner.as_str()
@@ -188,37 +194,6 @@ impl<T: PyPayload> ToPyObject for &'static PyInterned<T> {
     }
 }
 
-/// The unique reference of interned PyStr
-/// Always intended to be used as a static reference
-pub type PyStrInterned = PyInterned<PyStr>;
-
-impl PyStrInterned {
-    /// # Safety
-    /// the given cache must be alive while returned reference is alive
-    #[inline]
-    unsafe fn borrow_cache(cache: &CachedPyStrRef) -> &'static Self {
-        std::mem::transmute_copy(cache)
-    }
-
-    #[inline]
-    pub fn to_exact(&'static self) -> PyRefExact<PyStr> {
-        unsafe { PyRefExact::new_unchecked(self.to_owned()) }
-    }
-}
-
-impl std::fmt::Display for PyStrInterned {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        std::fmt::Display::fmt(self.as_str(), f)
-    }
-}
-
-impl AsRef<str> for PyStrInterned {
-    #[inline(always)]
-    fn as_ref(&self) -> &str {
-        self.as_str()
-    }
-}
-
 mod sealed {
     use crate::{
         builtins::PyStr,
diff --git a/vm/src/stdlib/sys.rs b/vm/src/stdlib/sys.rs
index d21229dfe..b342d1a85 100644
--- a/vm/src/stdlib/sys.rs
+++ b/vm/src/stdlib/sys.rs
@@ -512,8 +512,8 @@ mod sys {
     }
 
     #[pyfunction]
-    fn intern(s: PyRefExact<PyStr>, vm: &VirtualMachine) -> PyRefExact<PyStr> {
-        vm.ctx.intern_str(s).to_exact()
+    fn intern(s: PyRefExact<PyStr>, vm: &VirtualMachine) -> PyRef<PyStr> {
+        vm.ctx.intern_str(s).to_owned()
     }
 
     #[pyattr]
diff --git a/vm/src/vm/context.rs b/vm/src/vm/context.rs
index c4ec499a4..708d621c3 100644
--- a/vm/src/vm/context.rs
+++ b/vm/src/vm/context.rs
@@ -7,13 +7,13 @@ use crate::{
         object, pystr,
         type_::PyAttributes,
         PyBaseException, PyComplex, PyDict, PyDictRef, PyEllipsis, PyFloat, PyFrozenSet, PyInt,
-        PyIntRef, PyList, PyListRef, PyNone, PyNotImplemented, PyStr, PyTuple, PyTupleRef, PyType,
-        PyTypeRef,
+        PyIntRef, PyList, PyListRef, PyNone, PyNotImplemented, PyStr, PyStrInterned, PyTuple,
+        PyTupleRef, PyType, PyTypeRef,
     },
     class::{PyClassImpl, StaticType},
     exceptions,
     function::IntoPyNativeFunc,
-    intern::{Internable, MaybeInterned, PyStrInterned, StringPool},
+    intern::{Internable, MaybeInterned, StringPool},
     object::{PyObjectPayload, PyObjectRef, PyPayload, PyRef},
     types::{PyTypeFlags, PyTypeSlots, TypeZoo},
 };