diff --git a/pebble/asynchronous/process.py b/pebble/asynchronous/process.py
index f54e588..170a01e 100644
--- a/pebble/asynchronous/process.py
+++ b/pebble/asynchronous/process.py
@@ -22,7 +22,7 @@
 from itertools import count
 from functools import wraps
 from concurrent.futures import TimeoutError
-from typing import Any, Callable, Optional, Union, overload
+from typing import Any, Callable, Optional, overload
 
 from pebble import common
 from pebble.pool.process import ProcessPool
@@ -33,7 +33,6 @@ def process(
         func: Callable[[common.P], common.T]
 ) -> Callable[[common.P], asyncio.Future[common.T]]:
     ...
-
 @overload
 def process(
         name: Optional[str] = None,
@@ -44,11 +43,7 @@ def process(
 ) -> Callable[[Callable[[common.P], common.T]],
               Callable[[common.P], asyncio.Future[common.T]]]:
     ...
-
-def process(
-        *args: list,
-        **kwargs: dict
-) -> Callable:
+def process(*args, **kwargs):
     """Runs the decorated function in a concurrent process,
     taking care of the result and error management.
 
diff --git a/pebble/asynchronous/thread.py b/pebble/asynchronous/thread.py
index aed219c..5a23302 100644
--- a/pebble/asynchronous/thread.py
+++ b/pebble/asynchronous/thread.py
@@ -17,7 +17,7 @@
 import asyncio
 
 from functools import wraps
-from typing import Callable, Optional, Union, overload
+from typing import Callable, Optional, overload
 
 from pebble import common
 from pebble.pool.thread import ThreadPool
@@ -28,7 +28,6 @@ def thread(
         func: Callable[[common.P], common.T]
 ) -> Callable[[common.P], asyncio.Future[common.T]]:
     ...
-
 @overload
 def thread(
         name: Optional[str] = None,
@@ -37,11 +36,7 @@ def thread(
 ) -> Callable[[Callable[[common.P], common.T]],
               Callable[[common.P], asyncio.Future[common.T]]]:
     ...
-
-def thread(
-        *args: list,
-        **kwargs: dict
-) -> Callable:
+def thread(*args, **kwargs):
     """Runs the decorated function within a concurrent thread,
     taking care of the result and error management.
 
diff --git a/pebble/concurrent/process.py b/pebble/concurrent/process.py
index 59e6b2f..34ab1c4 100644
--- a/pebble/concurrent/process.py
+++ b/pebble/concurrent/process.py
@@ -21,7 +21,7 @@
 
 from itertools import count
 from functools import wraps
-from typing import Any, Callable, Optional, Union, overload
+from typing import Any, Callable, Optional, overload
 from concurrent.futures import CancelledError, TimeoutError
 
 from pebble import common
@@ -33,7 +33,6 @@ def process(
         func: Callable[[common.P], common.T]
 ) -> Callable[[common.P], common.ProcessFuture[common.T]]:
     ...
-
 @overload
 def process(
         name: Optional[str] = None,
@@ -44,13 +43,7 @@ def process(
 ) -> Callable[[Callable[[common.P], common.T]],
               Callable[[common.P], common.ProcessFuture[common.T]]]:
     ...
-
-def process(
-        *args: list,
-        **kwargs: dict
-) -> Union[Callable[[common.P], common.ProcessFuture[common.T]],
-           Callable[[Callable[[common.P], common.T]],
-                    Callable[[common.P], common.ProcessFuture[common.T]]]]:
+def process(*args, **kwargs):
     """Runs the decorated function in a concurrent process,
     taking care of the result and error management.
 
diff --git a/pebble/concurrent/thread.py b/pebble/concurrent/thread.py
index b53d54b..fd3a423 100644
--- a/pebble/concurrent/thread.py
+++ b/pebble/concurrent/thread.py
@@ -26,7 +26,6 @@ def thread(
         func: Callable[[common.P], common.T]
 ) -> Callable[[common.P], Future[common.T]]:
     ...
-
 @overload
 def thread(
         name: Optional[str] = None,
@@ -35,13 +34,7 @@ def thread(
 ) -> Callable[[Callable[[common.P], common.T]],
               Callable[[common.P], Future[common.T]]]:
     ...
-
-def thread(
-        *args: list,
-        **kwargs: dict
-) -> Union[Callable[[common.P], Future[common.T]],
-           Callable[[Callable[[common.P], common.T]],
-                    Callable[[common.P], Future[common.T]]]]:
+def thread(*args, **kwargs):
     """Runs the decorated function within a concurrent thread,
     taking care of the result and error management.