diff --git a/pywikibot/tools/djvu.py b/pywikibot/tools/djvu.py
index 3474f5f071..048a8a11de 100644
--- a/pywikibot/tools/djvu.py
+++ b/pywikibot/tools/djvu.py
@@ -87,6 +87,7 @@ def __str__(self) -> str:
         """Return a string representation."""
         return str("{}('{}')").format(self.__class__.__name__, self._filename)
 
+    @staticmethod
     def check_cache(fn):
         """Decorator to check if cache shall be cleared."""
         cache = ['_page_count', '_has_text', '_page_info']
@@ -100,6 +101,7 @@ def wrapper(obj, *args, **kwargs):
             return _res
         return wrapper
 
+    @staticmethod
     def check_page_number(fn):
         """Decorator to check if page number is valid.
 
@@ -312,8 +314,3 @@ def delete_page(self, n):
             assert self.page_info(new_ref_page, force=True) == ('', (sz, dpi))
 
         return True
-
-    # This is to be used only if this class is subclassed and the decorators
-    # needs to be used by the child.
-    check_page_number = staticmethod(check_page_number)
-    check_cache = staticmethod(check_cache)