diff --git a/src/sage/all.py b/src/sage/all.py
index 8c2514ecd96..a1a740a0018 100644
--- a/src/sage/all.py
+++ b/src/sage/all.py
@@ -274,6 +274,11 @@ def quit_sage(verbose=True):
 # sys.settrace(poison_currRing)
 
 
+# Deprecated leftover of monkey-patching inspect.isfunction() to support Cython functions.
+lazy_import('sage.misc.sageinspect', 'is_function_or_cython_function',
+            as_='isfunction', namespace=sage.__dict__, deprecation=32479)
+
+
 # Set a new random number seed as the very last thing
 # (so that printing initial_seed() and using that seed
 # in set_random_seed() will result in the same sequence you got at