diff --git a/icefall/utils.py b/icefall/utils.py
index fc372a6f6..d958bed13 100644
--- a/icefall/utils.py
+++ b/icefall/utils.py
@@ -1900,6 +1900,7 @@ def symlink_or_copy(exp_dir: Path, src: str, dst: str):
         copyfile(src=exp_dir / src, dst=exp_dir / dst)
     os.close(dir_fd)
 
+
 def num_tokens(
     token_table: k2.SymbolTable, disambig_pattern: str = re.compile(r"^#\d+$")
 ) -> int:
@@ -1917,4 +1918,4 @@ def num_tokens(
     num_tokens = len(ans)
     if 0 in ans:
         num_tokens -= 1
-    return num_tokens
\ No newline at end of file
+    return num_tokens