diff --git a/smalltag/_formats/_id3.py b/smalltag/_formats/_id3.py
index 831bf44..1b246f3 100644
--- a/smalltag/_formats/_id3.py
+++ b/smalltag/_formats/_id3.py
@@ -33,13 +33,7 @@ class _ID3(SmallTag, tinytag._ID3):
             if len(frame_id) == 4:
                 self._ID3_WRITE_MAPPING[name] = frame_id
 
-        new_frames = self._compose_id3v2_frames()
-
-        size = len(new_frames)
-
-        new_header = self._compose_id3v2_header(size)
-
-        new_tag = new_header + new_frames
+        new_tag = self._compose_id3v2_tag()
 
         size, extended, major = self._parse_id3v2_header(self._filehandler)
 
@@ -53,7 +47,17 @@ class _ID3(SmallTag, tinytag._ID3):
         if should_close_file:
             self._filehandler.close()
 
-    def _compose_id3v2_header(self, size: int):
+    def _compose_id3v2_tag(self) -> bytes:
+        frames = self._compose_id3v2_frames()
+        frame_size = len(frames)
+
+        header = self._compose_id3v2_header(frame_size)
+
+        tag = header + frames
+
+        return tag
+
+    def _compose_id3v2_header(self, size: int) -> bytes:
         header = b"ID3\x04\x00\x00"
 
         synchsafe_size = self._synchsafe(size)
@@ -61,7 +65,7 @@ class _ID3(SmallTag, tinytag._ID3):
 
         return header
 
-    def _compose_id3v2_frames(self):
+    def _compose_id3v2_frames(self) -> bytes:
         tag_dict = self.as_dict()
 
         frames = b""
@@ -74,7 +78,7 @@ class _ID3(SmallTag, tinytag._ID3):
 
         return frames
 
-    def _compose_id3v2_frame(self, field_name, field_value):
+    def _compose_id3v2_frame(self, field_name, field_value) -> bytes:
         frame_id = bytes(self._ID3_WRITE_MAPPING[field_name], "ISO-8859-1")
 
         field_value = field_value[0]