remove unnecessary check for existing value

Lib/functools.py

@@ -959,8 +959,6 @@ def __isabstractmethod__(self):
 ### cached_property() - computed once per instance, cached as attribute
 ################################################################################
 
-_NOT_FOUND = object()
-
 
 class cached_property:
     def __init__(self, func):
@@ -991,17 +989,15 @@ def __get__(self, instance, owner=None):
                 f"instance to cache {self.attrname!r} property."
             )
             raise TypeError(msg) from None
-        val = cache.get(self.attrname, _NOT_FOUND)
-        if val is _NOT_FOUND:
-            val = self.func(instance)
-            try:
-                cache[self.attrname] = val
-            except TypeError:
-                msg = (
-                    f"The '__dict__' attribute on {type(instance).__name__!r} instance "
-                    f"does not support item assignment for caching {self.attrname!r} property."
-                )
-                raise TypeError(msg) from None
+        val = self.func(instance)
+        try:
+            cache[self.attrname] = val
+        except TypeError:
+            msg = (
+                f"The '__dict__' attribute on {type(instance).__name__!r} instance "
+                f"does not support item assignment for caching {self.attrname!r} property."
+            )
+            raise TypeError(msg) from None
         return val
 
     __class_getitem__ = classmethod(GenericAlias)