@@ -72,7 +72,7 @@ def install_environment(
 
 
 def run_hook(
-        hook: 'Hook',
+        hook: Hook,
         file_args: Sequence[str],
         color: bool,
 ) -> Tuple[int, bytes]:
 
@@ -97,7 +97,7 @@ def docker_cmd() -> Tuple[str, ...]:  # pragma: windows no cover
 
 
 def run_hook(
-        hook: 'Hook',
+        hook: Hook,
         file_args: Sequence[str],
         color: bool,
 ) -> Tuple[int, bytes]:  # pragma: windows no cover
 
@@ -13,7 +13,7 @@
 
 
 def run_hook(
-        hook: 'Hook',
+        hook: Hook,
         file_args: Sequence[str],
         color: bool,
 ) -> Tuple[int, bytes]:  # pragma: windows no cover
 
@@ -11,7 +11,7 @@
 
 
 def run_hook(
-        hook: 'Hook',
+        hook: Hook,
         file_args: Sequence[str],
         color: bool,
 ) -> Tuple[int, bytes]:
 
@@ -89,7 +89,7 @@ def install_environment(
 
 
 def run_hook(
-        hook: 'Hook',
+        hook: Hook,
         file_args: Sequence[str],
         color: bool,
 ) -> Tuple[int, bytes]:
 
@@ -72,7 +72,7 @@ def no_install(
     raise AssertionError('This type is not installable')
 
 
-def target_concurrency(hook: 'Hook') -> int:
+def target_concurrency(hook: Hook) -> int:
     if hook.require_serial or 'PRE_COMMIT_NO_CONCURRENCY' in os.environ:
         return 1
     else:
@@ -97,7 +97,7 @@ def _shuffled(seq: Sequence[str]) -> List[str]:
 
 
 def run_xargs(
-        hook: 'Hook',
+        hook: Hook,
         cmd: Tuple[str, ...],
         file_args: Sequence[str],
         **kwargs: Any,
 
@@ -85,7 +85,7 @@ def install_environment(
 
 
 def run_hook(
-        hook: 'Hook',
+        hook: Hook,
         file_args: Sequence[str],
         color: bool,
 ) -> Tuple[int, bytes]:
 
@@ -59,7 +59,7 @@ def install_environment(
 
 
 def run_hook(
-        hook: 'Hook',
+        hook: Hook,
         file_args: Sequence[str],
         color: bool,
 ) -> Tuple[int, bytes]:
 
@@ -46,7 +46,7 @@ def _process_filename_at_once(pattern: Pattern[bytes], filename: str) -> int:
 
 
 def run_hook(
-        hook: 'Hook',
+        hook: Hook,
         file_args: Sequence[str],
         color: bool,
 ) -> Tuple[int, bytes]:
 
@@ -145,7 +145,7 @@ def py_interface(
 ) -> Tuple[
     Callable[[Prefix, str], ContextManager[None]],
     Callable[[Prefix, str], bool],
-    Callable[['Hook', Sequence[str], bool], Tuple[int, bytes]],
+    Callable[[Hook, Sequence[str], bool], Tuple[int, bytes]],
     Callable[[Prefix, str, Sequence[str]], None],
 ]:
     @contextlib.contextmanager
@@ -168,7 +168,7 @@ def healthy(prefix: Prefix, language_version: str) -> bool:
         return retcode == 0
 
     def run_hook(
-            hook: 'Hook',
+            hook: Hook,
             file_args: Sequence[str],
             color: bool,
     ) -> Tuple[int, bytes]: