diff --git a/pandas/core/arrays/base.py b/pandas/core/arrays/base.py
index f3325f6ffd9d9..53ae1094c6765 100644
--- a/pandas/core/arrays/base.py
+++ b/pandas/core/arrays/base.py
@@ -27,8 +27,6 @@
 from pandas.core.missing import backfill_1d, pad_1d
 from pandas.core.sorting import nargsort
 
-_not_implemented_message = "{} does not implement {}."
-
 _extension_array_shared_docs: Dict[str, str] = dict()
 
 
@@ -330,9 +328,7 @@ def __setitem__(self, key: Union[int, np.ndarray], value: Any) -> None:
         #   __init__ method coerces that value, then so should __setitem__
         # Note, also, that Series/DataFrame.where internally use __setitem__
         # on a copy of the data.
-        raise NotImplementedError(
-            _not_implemented_message.format(type(self), "__setitem__")
-        )
+        raise NotImplementedError(f"{type(self)} does not implement __setitem__.")
 
     def __len__(self) -> int:
         """