diff --git a/src/tja2fumen/parsers.py b/src/tja2fumen/parsers.py
index 5cb3cdd..aeb0404 100644
--- a/src/tja2fumen/parsers.py
+++ b/src/tja2fumen/parsers.py
@@ -1,8 +1,8 @@
 import os
 import re
+import struct
 from copy import deepcopy
 
-from tja2fumen.utils import read_struct
 from tja2fumen.types import (TJASong, TJAMeasure, TJAData, FumenCourse,
                              FumenMeasure, FumenBranch, FumenNote, FumenHeader)
 from tja2fumen.constants import (NORMALIZE_COURSE, TJA_NOTE_TYPES,
@@ -393,3 +393,31 @@ def read_fumen(fumen_file, exclude_empty_measures=False):
                          or m.branches['master'].length]
 
     return song
+
+
+def read_struct(file, order, format_string, seek=None):
+    """
+    Interpret bytes as packed binary data.
+
+    Arguments:
+        - file: The fumen's file object (presumably in 'rb' mode).
+        - order: '<' or '>' (little or big endian).
+        - format_string: String made up of format characters that describes
+                         the data layout. Full list of available characters:
+          (https://docs.python.org/3/library/struct.html#format-characters)
+        - seek: The position of the read pointer to be used within the file.
+
+    Return values:
+        - interpreted_string: A string containing interpreted byte values,
+                              based on the specified 'fmt' format characters.
+    """
+    if seek:
+        file.seek(seek)
+    expected_size = struct.calcsize(order + format_string)
+    byte_string = file.read(expected_size)
+    # One "official" fumen (AC11\deo\deo_n.bin) runs out of data early
+    # This workaround fixes the issue by appending 0's to get the size to match
+    if len(byte_string) != expected_size:
+        byte_string += (b'\x00' * (expected_size - len(byte_string)))
+    interpreted_string = struct.unpack(order + format_string, byte_string)
+    return interpreted_string
diff --git a/src/tja2fumen/utils.py b/src/tja2fumen/utils.py
deleted file mode 100644
index bcc7e91..0000000
--- a/src/tja2fumen/utils.py
+++ /dev/null
@@ -1,36 +0,0 @@
-import struct
-
-
-def read_struct(file, order, format_string, seek=None):
-    """
-    Interpret bytes as packed binary data.
-
-    Arguments:
-        - file: The fumen's file object (presumably in 'rb' mode).
-        - order: '<' or '>' (little or big endian).
-        - format_string: String made up of format characters that describes
-                         the data layout. Full list of available characters:
-          (https://docs.python.org/3/library/struct.html#format-characters)
-        - seek: The position of the read pointer to be used within the file.
-
-    Return values:
-        - interpreted_string: A string containing interpreted byte values,
-                              based on the specified 'fmt' format characters.
-    """
-    if seek:
-        file.seek(seek)
-    expected_size = struct.calcsize(order + format_string)
-    byte_string = file.read(expected_size)
-    # One "official" fumen (AC11\deo\deo_n.bin) runs out of data early
-    # This workaround fixes the issue by appending 0's to get the size to match
-    if len(byte_string) != expected_size:
-        byte_string += (b'\x00' * (expected_size - len(byte_string)))
-    interpreted_string = struct.unpack(order + format_string, byte_string)
-    return interpreted_string
-
-
-def write_struct(file, order, format_string, value_list, seek=None):
-    if seek:
-        file.seek(seek)
-    packed_bytes = struct.pack(order + format_string, *value_list)
-    file.write(packed_bytes)
diff --git a/src/tja2fumen/writers.py b/src/tja2fumen/writers.py
index 34bfeaa..080d209 100644
--- a/src/tja2fumen/writers.py
+++ b/src/tja2fumen/writers.py
@@ -1,4 +1,5 @@
-from tja2fumen.utils import write_struct
+import struct
+
 from tja2fumen.constants import BRANCH_NAMES, FUMEN_TYPE_NOTES
 
 
@@ -38,3 +39,10 @@ def write_fumen(path_out, song):
 
                     if note.type.lower() == "drumroll":
                         file.write(note.drumroll_bytes)
+
+
+def write_struct(file, order, format_string, value_list, seek=None):
+    if seek:
+        file.seek(seek)
+    packed_bytes = struct.pack(order + format_string, *value_list)
+    file.write(packed_bytes)