diff --git a/pypdf/_utils.py b/pypdf/_utils.py
index 20d14c387..df652d4d7 100644
--- a/pypdf/_utils.py
+++ b/pypdf/_utils.py
@@ -202,11 +202,7 @@ def check_if_whitespace_only(value: bytes) -> bool:
         True if the value only has whitespace characters, otherwise return False.
 
     """
-    for index in range(len(value)):
-        current = value[index : index + 1]
-        if current not in WHITESPACES:
-            return False
-    return True
+    return all(b in WHITESPACES_AS_BYTES for b in value)
 
 
 def skip_over_comment(stream: StreamType) -> None: