TYP: Use Protocol for ReaderBase (#52915)

Author: mroeschke

pandas/io/sas/sasreader.py

@@ -3,13 +3,10 @@
 """
 from __future__ import annotations
 
-from abc import (
-    ABCMeta,
-    abstractmethod,
-)
 from typing import (
     TYPE_CHECKING,
     Hashable,
+    Protocol,
     overload,
 )
 
@@ -31,19 +28,16 @@
     from pandas import DataFrame
 
 
-# TODO(PY38): replace with Protocol in Python 3.8
-class ReaderBase(metaclass=ABCMeta):
+class ReaderBase(Protocol):
     """
     Protocol for XportReader and SAS7BDATReader classes.
     """
 
-    @abstractmethod
     def read(self, nrows: int | None = None) -> DataFrame:
-        pass
+        ...
 
-    @abstractmethod
     def close(self) -> None:
-        pass
+        ...
 
     def __enter__(self) -> ReaderBase:
         return self