diff --git a/tz.cpp b/tz.cpp
index d346319..dd18d6a 100644
--- a/tz.cpp
+++ b/tz.cpp
@@ -354,12 +354,20 @@ tzdb_list::erase_after(const_iterator p) noexcept
     return ++p;
 }
 
+struct tzdb_list::undocumented_helper
+{
+    static void push_front(tzdb_list& db_list, TZ_DB* tzdb) noexcept
+    {
+        db_list.push_front(tzdb);
+    }
+};
+
 static
 tzdb_list
 create_tzdb()
 {
     tzdb_list tz_db;
-    tz_db.push_front(init_tzdb().release());
+    tzdb_list::undocumented_helper::push_front(tz_db, init_tzdb().release());
     return tz_db;
 }
 
@@ -3365,7 +3373,7 @@ reload_tzdb()
     if (!v.empty() && v == remote_version())
         return get_tzdb_list().front();
 #endif  // AUTO_DOWNLOAD
-    get_tzdb_list().push_front(init_tzdb().release());
+    tzdb_list::undocumented_helper::push_front(get_tzdb_list(), init_tzdb().release());
     return get_tzdb_list().front();
 }
 
diff --git a/tz.h b/tz.h
index fb2667a..f2943d7 100644
--- a/tz.h
+++ b/tz.h
@@ -1194,7 +1194,6 @@ public:
     tzdb_list() = default;
     tzdb_list(tzdb_list&& x) noexcept;
 
-    void push_front(TZ_DB* tzdb) noexcept;
     const TZ_DB& front() const noexcept {return *head_;}
 
     class const_iterator;
@@ -1206,6 +1205,10 @@ public:
     const_iterator cend() const noexcept;
 
     const_iterator erase_after(const_iterator p) noexcept;
+
+    struct undocumented_helper;
+private:
+    void push_front(TZ_DB* tzdb) noexcept;
 };
 
 class tzdb_list::const_iterator