diff --git a/python/map.c b/python/map.c
index 4b6e97e193..1e2b3806b6 100644
--- a/python/map.c
+++ b/python/map.c
@@ -259,16 +259,6 @@ static Py_ssize_t PyUpb_MapContainer_Length(PyObject* _self) {
   return map ? upb_Map_Size(map) : 0;
 }
 
-static PyUpb_MapContainer* PyUpb_MapContainer_Check(PyObject* _self) {
-  PyUpb_ModuleState* state = PyUpb_ModuleState_Get();
-  if (!PyObject_TypeCheck(_self, state->message_map_container_type) &&
-      !PyObject_TypeCheck(_self, state->scalar_map_container_type)) {
-    PyErr_Format(PyExc_TypeError, "Expected protobuf map, but got %R", _self);
-    return NULL;
-  }
-  return (PyUpb_MapContainer*)_self;
-}
-
 int PyUpb_Message_InitMapAttributes(PyObject* map, PyObject* value,
                                     const upb_FieldDef* f);
 
diff --git a/python/message.c b/python/message.c
index f31aa5e734..8d91b0fe4e 100644
--- a/python/message.c
+++ b/python/message.c
@@ -1665,7 +1665,6 @@ static PyObject* PyUpb_Message_WhichOneof(PyObject* _self, PyObject* name) {
 }
 
 PyObject* DeepCopy(PyObject* _self, PyObject* arg) {
-  PyUpb_Message* self = (void*)_self;
   const upb_MessageDef* def = PyUpb_Message_GetMsgdef(_self);
   const upb_MiniTable* mini_table = upb_MessageDef_MiniTable(def);
   upb_Message* msg = PyUpb_Message_GetIfReified(_self);
diff --git a/python/protobuf.c b/python/protobuf.c
index 316b1f6603..82b690ea3f 100644
--- a/python/protobuf.c
+++ b/python/protobuf.c
@@ -216,7 +216,7 @@ typedef struct {
 // memory to the OS.  Without this call, we appear to leak memory, at least
 // as measured in RSS.
 //
-// We opt not to use this instead of PyMalloc (which would also solve the
+// We opt to use this instead of PyMalloc (which would also solve the
 // problem) because the latter requires the GIL to be held.  This would make
 // our messages unsafe to share with other languages that could free at
 // unpredictable
@@ -240,7 +240,7 @@ static void* upb_trim_allocfunc(upb_alloc* alloc, void* ptr, size_t oldsize,
   }
 }
 static upb_alloc trim_alloc = {&upb_trim_allocfunc};
-static const upb_alloc* global_alloc = &trim_alloc;
+static upb_alloc* global_alloc = &trim_alloc;
 // end:github_only
 
 static upb_Arena* PyUpb_NewArena(void) {