Replace abc.ABCMeta with abc.ABC

tenacity/__init__.py

@@ -22,7 +22,7 @@
 import time
 import typing as t
 import warnings
-from abc import ABCMeta, abstractmethod
+from abc import ABC, abstractmethod
 from concurrent import futures
 from inspect import iscoroutinefunction
 
@@ -225,7 +225,7 @@ def __exit__(
             return None
 
 
-class BaseRetrying(metaclass=ABCMeta):
+class BaseRetrying(ABC):
     def __init__(
         self,
         sleep: t.Callable[[t.Union[int, float]], None] = sleep,

tenacity/retry.py

@@ -22,7 +22,7 @@
     from tenacity import RetryCallState
 
 
-class retry_base(metaclass=abc.ABCMeta):
+class retry_base(abc.ABC):
     """Abstract base class for retry strategies."""
 
     @abc.abstractmethod

tenacity/stop.py

@@ -22,7 +22,7 @@
     from tenacity import RetryCallState
 
 
-class stop_base(metaclass=abc.ABCMeta):
+class stop_base(abc.ABC):
     """Abstract base class for stop strategies."""
 
     @abc.abstractmethod

tenacity/wait.py

@@ -24,7 +24,7 @@
     from tenacity import RetryCallState
 
 
-class wait_base(metaclass=abc.ABCMeta):
+class wait_base(abc.ABC):
     """Abstract base class for wait strategies."""
 
     @abc.abstractmethod