Make optional types explicit

docs/includes/settingref.txt

@@ -1436,7 +1436,7 @@ consider doing retries (send to separate topic):
    main_topic = app.topic('main')
    deadletter_topic = app.topic('main_deadletter')
 
-   async def send_request(value, timeout: float = None) -> None:
+   async def send_request(value, timeout: Optional[float] = None) -> None:
        await app.http_client.get('http://foo.com', timeout=timeout)
 
    @app.agent(main_topic)

docs/userguide/application.rst

@@ -856,8 +856,8 @@ This can be used to attach custom headers to Kafka messages:
             sender: AppT,
             key: bytes = None,
             value: bytes = None,
-            partition: int = None,
-            timestamp: float = None,
+            partition: Optional[int] = None,
+            timestamp: Optional[float] = None,
             headers: List[Tuple[str, bytes]] = None,
             **kwargs: Any) -> None:
         test = current_test()

docs/userguide/models.rst

@@ -601,8 +601,8 @@ time and last modified time:
 .. sourcecode:: python
 
     class MyBaseRecord(Record, abstract=True):
-        time_created: float = None
-        time_modified: float = None
+        time_created: Optional[float] = None
+        time_modified: Optional[float] = None
 
 Inherit from this model to create a new model
 having the fields by default:

faust/agents/actor.py

@@ -1,5 +1,5 @@
 """Actor - Individual Agent instances."""
-from typing import Any, AsyncGenerator, AsyncIterator, Coroutine, Set, cast
+from typing import Any, AsyncGenerator, AsyncIterator, Coroutine, Optional, Set, cast
 
 from mode import Service
 from mode.utils.tracebacks import format_agen_stack, format_coro_stack
@@ -22,8 +22,8 @@ def __init__(
         agent: AgentT,
         stream: StreamT,
         it: _T,
-        index: int = None,
-        active_partitions: Set[TP] = None,
+        index: Optional[int] = None,
+        active_partitions: Optional[Set[TP]] = None,
         **kwargs: Any,
     ) -> None:
         self.agent = agent

faust/agents/agent.py

@@ -183,18 +183,18 @@ def __init__(
         fun: AgentFun,
         *,
         app: AppT,
-        name: str = None,
+        name: Optional[str] = None,
         channel: Union[str, ChannelT] = None,
         concurrency: int = 1,
         sink: Iterable[SinkT] = None,
         on_error: AgentErrorHandler = None,
         supervisor_strategy: Type[SupervisorStrategyT] = None,
-        help: str = None,
-        schema: SchemaT = None,
+        help: Optional[str] = None,
+        schema: Optional[SchemaT] = None,
         key_type: ModelArg = None,
         value_type: ModelArg = None,
         isolated_partitions: bool = False,
-        use_reply_headers: bool = None,
+        use_reply_headers: Optional[bool] = None,
         **kwargs: Any,
     ) -> None:
         self.app = app
@@ -242,8 +242,8 @@ async def _start_one(
         *,
         index: Optional[int] = None,
         active_partitions: Optional[Set[TP]] = None,
-        stream: StreamT = None,
-        channel: ChannelT = None,
+        stream: Optional[StreamT] = None,
+        channel: Optional[ChannelT] = None,
     ) -> ActorT:
         # an index of None means there's only one instance,
         # and `index is None` is used as a test by functions that
@@ -261,7 +261,7 @@ async def _start_one_supervised(
         self,
         index: Optional[int] = None,
         active_partitions: Optional[Set[TP]] = None,
-        stream: StreamT = None,
+        stream: Optional[StreamT] = None,
     ) -> ActorT:
         aref = await self._start_one(
             index=index,
@@ -456,7 +456,7 @@ def clone(self, *, cls: Type[AgentT] = None, **kwargs: Any) -> AgentT:
 
     def test_context(
         self,
-        channel: ChannelT = None,
+        channel: Optional[ChannelT] = None,
         supervisor_strategy: SupervisorStrategyT = None,
         on_error: AgentErrorHandler = None,
         **kwargs: Any,
@@ -487,7 +487,7 @@ def _prepare_channel(
         self,
         channel: Union[str, ChannelT] = None,
         internal: bool = True,
-        schema: SchemaT = None,
+        schema: Optional[SchemaT] = None,
         key_type: ModelArg = None,
         value_type: ModelArg = None,
         **kwargs: Any,
@@ -514,10 +514,10 @@ def _prepare_channel(
     def __call__(
         self,
         *,
-        index: int = None,
-        active_partitions: Set[TP] = None,
-        stream: StreamT = None,
-        channel: ChannelT = None,
+        index: Optional[int] = None,
+        active_partitions: Optional[Set[TP]] = None,
+        stream: Optional[StreamT] = None,
+        channel: Optional[ChannelT] = None,
     ) -> ActorRefT:
         """Create new actor instance for this agent."""
         # The agent function can be reused by other agents/tasks.
@@ -545,9 +545,9 @@ def actor_from_stream(
         self,
         stream: Optional[StreamT],
         *,
-        index: int = None,
-        active_partitions: Set[TP] = None,
-        channel: ChannelT = None,
+        index: Optional[int] = None,
+        active_partitions: Optional[Set[TP]] = None,
+        channel: Optional[ChannelT] = None,
     ) -> ActorRefT:
         """Create new actor from stream."""
         we_created_stream = False
@@ -601,7 +601,10 @@ def add_sink(self, sink: SinkT) -> None:
             self._sinks.append(sink)
 
     def stream(
-        self, channel: ChannelT = None, active_partitions: Set[TP] = None, **kwargs: Any
+        self,
+        channel: Optional[ChannelT] = None,
+        active_partitions: Optional[Set[TP]] = None,
+        **kwargs: Any,
     ) -> StreamT:
         """Create underlying stream used by this agent."""
         if channel is None:
@@ -631,9 +634,9 @@ async def _start_task(
         *,
         index: Optional[int],
         active_partitions: Optional[Set[TP]] = None,
-        stream: StreamT = None,
-        channel: ChannelT = None,
-        beacon: NodeT = None,
+        stream: Optional[StreamT] = None,
+        channel: Optional[ChannelT] = None,
+        beacon: Optional[NodeT] = None,
     ) -> ActorRefT:
         # If the agent is an async function we simply start it,
         # if it returns an AsyncIterable/AsyncGenerator we start a task
@@ -750,8 +753,8 @@ async def cast(
         value: V = None,
         *,
         key: K = None,
-        partition: int = None,
-        timestamp: float = None,
+        partition: Optional[int] = None,
+        timestamp: Optional[float] = None,
         headers: HeadersArg = None,
     ) -> None:
         """RPC operation: like :meth:`ask` but do not expect reply.
@@ -772,11 +775,11 @@ async def ask(
         value: V = None,
         *,
         key: K = None,
-        partition: int = None,
-        timestamp: float = None,
+        partition: Optional[int] = None,
+        timestamp: Optional[float] = None,
         headers: HeadersArg = None,
         reply_to: ReplyToArg = None,
-        correlation_id: str = None,
+        correlation_id: Optional[str] = None,
     ) -> Any:
         """RPC operation: ask agent for result of processing value.
 
@@ -803,11 +806,11 @@ async def ask_nowait(
         value: V = None,
         *,
         key: K = None,
-        partition: int = None,
-        timestamp: float = None,
+        partition: Optional[int] = None,
+        timestamp: Optional[float] = None,
         headers: HeadersArg = None,
         reply_to: ReplyToArg = None,
-        correlation_id: str = None,
+        correlation_id: Optional[str] = None,
         force: bool = False,
     ) -> ReplyPromise:
         """RPC operation: ask agent for result of processing value.
@@ -835,7 +838,7 @@ def _create_req(
         key: K = None,
         value: V = None,
         reply_to: ReplyToArg = None,
-        correlation_id: str = None,
+        correlation_id: Optional[str] = None,
         headers: HeadersArg = None,
     ) -> Tuple[V, Optional[HeadersArg]]:
         if reply_to is None:
@@ -871,14 +874,14 @@ async def send(
         *,
         key: K = None,
         value: V = None,
-        partition: int = None,
-        timestamp: float = None,
+        partition: Optional[int] = None,
+        timestamp: Optional[float] = None,
         headers: HeadersArg = None,
         key_serializer: CodecArg = None,
         value_serializer: CodecArg = None,
-        callback: MessageSentCallback = None,
+        callback: Optional[MessageSentCallback] = None,
         reply_to: ReplyToArg = None,
-        correlation_id: str = None,
+        correlation_id: Optional[str] = None,
         force: bool = False,
     ) -> Awaitable[RecordMetadata]:
         """Send message to topic used by agent."""
@@ -1091,7 +1094,7 @@ class AgentTestWrapper(Agent, AgentTestWrapperT):  # pragma: no cover
     _stream: StreamT
 
     def __init__(
-        self, *args: Any, original_channel: ChannelT = None, **kwargs: Any
+        self, *args: Any, original_channel: Optional[ChannelT] = None, **kwargs: Any
     ) -> None:
         super().__init__(*args, **kwargs)
         self.results = {}
@@ -1131,7 +1134,7 @@ async def put(
         value_serializer: CodecArg = None,
         *,
         reply_to: ReplyToArg = None,
-        correlation_id: str = None,
+        correlation_id: Optional[str] = None,
         wait: bool = True,
     ) -> EventT:
         if reply_to:
@@ -1164,7 +1167,7 @@ def to_message(
         *,
         partition: Optional[int] = None,
         offset: int = 0,
-        timestamp: float = None,
+        timestamp: Optional[float] = None,
         timestamp_type: int = 0,
         headers: HeadersArg = None,
     ) -> Message:

faust/app/_attached.py

@@ -13,6 +13,7 @@
     List,
     MutableMapping,
     NamedTuple,
+    Optional,
     Union,
     cast,
 )
@@ -91,13 +92,13 @@ async def maybe_put(
         channel: Union[ChannelT, str],
         key: K = None,
         value: V = None,
-        partition: int = None,
-        timestamp: float = None,
+        partition: Optional[int] = None,
+        timestamp: Optional[float] = None,
         headers: HeadersArg = None,
-        schema: SchemaT = None,
+        schema: Optional[SchemaT] = None,
         key_serializer: CodecArg = None,
         value_serializer: CodecArg = None,
-        callback: MessageSentCallback = None,
+        callback: Optional[MessageSentCallback] = None,
         force: bool = False,
     ) -> Awaitable[RecordMetadata]:
         """Attach message to source topic offset.
@@ -145,13 +146,13 @@ def put(
         channel: Union[str, ChannelT],
         key: K,
         value: V,
-        partition: int = None,
-        timestamp: float = None,
+        partition: Optional[int] = None,
+        timestamp: Optional[float] = None,
         headers: HeadersArg = None,
-        schema: SchemaT = None,
+        schema: Optional[SchemaT] = None,
         key_serializer: CodecArg = None,
         value_serializer: CodecArg = None,
-        callback: MessageSentCallback = None,
+        callback: Optional[MessageSentCallback] = None,
     ) -> Awaitable[RecordMetadata]:
         """Attach message to source topic offset."""
         # This attaches message to be published when source message' is