used typing.TYPE_CHECKING instead of False

promise/async_.py

@@ -1,10 +1,11 @@
 # Based on https://github.com/petkaantonov/bluebird/blob/master/src/promise.js
 from collections import deque
 from threading import local
+from typing import TYPE_CHECKING
 
-if False:
+if TYPE_CHECKING:
     from .promise import Promise
-    from typing import Any, Callable, Optional, Union  # flake8: noqa
+    from typing import Any, Callable, Optional, Union
 
 
 class Async(local):

promise/dataloader.py

@@ -5,10 +5,11 @@
     from collections import Iterable
 from functools import partial
 from threading import local
+from typing import TYPE_CHECKING
 
 from .promise import Promise, async_instance, get_default_scheduler
 
-if False:
+if TYPE_CHECKING:
     from typing import (
         Any,
         List,

promise/iterate_promise.py

@@ -1,5 +1,7 @@
 # flake8: noqa
-if False:
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
     from .promise import Promise
     from typing import Iterator
 

promise/promise.py

@@ -16,13 +16,13 @@
 from .utils import deprecated, integer_types, string_types, text_type, binary_type, warn
 from .promise_list import PromiseList
 from .schedulers.immediate import ImmediateScheduler
-from typing import TypeVar, Generic
+from typing import TypeVar, Generic, TYPE_CHECKING
 
 # from .schedulers.gevent import GeventScheduler
 # from .schedulers.asyncio import AsyncioScheduler
 # from .schedulers.thread import ThreadScheduler
 
-if False:
+if TYPE_CHECKING:
     from typing import (
         Type,
         List,

promise/promise_list.py

@@ -4,15 +4,14 @@
     from collections.abc import Iterable
 except ImportError:
     from collections import Iterable
+from typing import TYPE_CHECKING
 
-if False:
+if TYPE_CHECKING:
     from .promise import Promise
     from typing import (
         Any,
         Optional,
-        Tuple,
         Union,
-        List,
         Type,
         Collection,
     )  # flake8: noqa