Improve ext.asyncio.result (#50)

* Improve `ext.asyncio.result`

* Updates based on PR feedback

Author: bryanforbes

sqlalchemy-stubs/ext/asyncio/result.pyi

@@ -1,73 +1,91 @@
 from typing import Any
-from typing import Int
 from typing import Iterator
 from typing import List
 from typing import Mapping
 from typing import Optional
+from typing import TypeVar
 
-from ... import util as util
-from ...engine.result import FilterResult as FilterResult
-from ...engine.result import FrozenResult as FrozenResult
-from ...engine.result import MergedResult as MergedResult
-from ...engine.result import Row as Row
-from ...util.concurrency import greenlet_spawn as greenlet_spawn
+from ...engine.result import FilterResult
+from ...engine.result import FrozenResult
+from ...engine.result import MergedResult
+from ...engine.result import Result
+from ...engine.result import RMKeyView
+from ...engine.result import Row
+
+_TAsyncResult = TypeVar("_TAsyncResult", bound=AsyncResult)
+_TAsyncScalarResult = TypeVar("_TAsyncScalarResult", bound=AsyncScalarResult)
+_TAsyncMappingResult = TypeVar(
+    "_TAsyncMappingResult", bound=AsyncMappingResult
+)
 
 class AsyncCommon(FilterResult):
     async def close(self) -> None: ...
 
 class AsyncResult(AsyncCommon):
-    def __init__(self, real_result: Any) -> None: ...
-    def keys(self): ...
-    def unique(self, strategy: Optional[Any] = ...): ...
-    def columns(self, *col_expressions: object) -> AsyncResult: ...
+    def __init__(self, real_result: Result) -> None: ...
+    def keys(self) -> RMKeyView: ...
+    def unique(
+        self: _TAsyncResult, strategy: Optional[Any] = ...
+    ) -> _TAsyncResult: ...
+    def columns(
+        self: _TAsyncResult, *col_expressions: Any
+    ) -> _TAsyncResult: ...
     async def partitions(
-        self, size: Optional[Int] = ...
+        self, size: Optional[int] = ...
     ) -> Iterator[List[Any]]: ...
-    async def fetchone(self) -> Row: ...
-    async def fetchmany(self, size: Optional[Int] = ...) -> List[Row]: ...
+    async def fetchone(self) -> Optional[Row]: ...
+    async def fetchmany(self, size: Optional[int] = ...) -> List[Row]: ...
     async def all(self) -> List[Row]: ...
-    def __aiter__(self): ...
-    async def __anext__(self): ...
-    async def first(self) -> Row: ...
+    def __aiter__(self: _TAsyncResult) -> _TAsyncResult: ...
+    async def __anext__(self) -> Row: ...
+    async def first(self) -> Optional[Row]: ...
     async def one_or_none(self) -> Optional[Row]: ...
     async def scalar_one(self) -> Any: ...
     async def scalar_one_or_none(self) -> Optional[Any]: ...
     async def one(self) -> Row: ...
     async def scalar(self) -> Optional[Any]: ...
-    async def freeze(self): ...
-    def merge(self, *others: Any): ...
-    def scalars(self, index: Int = ...) -> AsyncScalarResult: ...
-    def mappings(self): ...
+    async def freeze(self) -> FrozenResult: ...
+    def merge(self, *others: Any) -> MergedResult: ...
+    def scalars(self, index: int = ...) -> AsyncScalarResult: ...
+    def mappings(self) -> AsyncMappingResult: ...
 
 class AsyncScalarResult(AsyncCommon):
-    def __init__(self, real_result: Any, index: Any) -> None: ...
-    def unique(self, strategy: Optional[Any] = ...): ...
+    def __init__(self, real_result: AsyncResult, index: Any) -> None: ...
+    def unique(
+        self: _TAsyncScalarResult, strategy: Optional[Any] = ...
+    ) -> _TAsyncScalarResult: ...
     async def partitions(
-        self, size: Optional[Int] = ...
+        self, size: Optional[int] = ...
     ) -> Iterator[List[Any]]: ...
     async def fetchall(self) -> List[Any]: ...
-    async def fetchmany(self, size: Optional[Int] = ...) -> List[Any]: ...
+    async def fetchmany(self, size: Optional[int] = ...) -> List[Any]: ...
     async def all(self) -> List[Any]: ...
-    def __aiter__(self): ...
-    async def __anext__(self): ...
+    def __aiter__(self: _TAsyncScalarResult) -> _TAsyncScalarResult: ...
+    async def __anext__(self) -> Any: ...
     async def first(self) -> Optional[Any]: ...
     async def one_or_none(self) -> Optional[Any]: ...
     async def one(self) -> Any: ...
 
 class AsyncMappingResult(AsyncCommon):
-    def __init__(self, result: Any) -> None: ...
-    def keys(self): ...
-    def unique(self, strategy: Optional[Any] = ...): ...
-    def columns(self, *col_expressions: object) -> AsyncMappingResult: ...
+    def __init__(self, result: AsyncResult) -> None: ...
+    def keys(self) -> RMKeyView: ...
+    def unique(
+        self: _TAsyncMappingResult, strategy: Optional[Any] = ...
+    ) -> _TAsyncMappingResult: ...
+    def columns(
+        self: _TAsyncMappingResult, *col_expressions: Any
+    ) -> _TAsyncMappingResult: ...
     async def partitions(
-        self, size: Optional[Int] = ...
-    ) -> Iterator[List[Mapping]]: ...
-    async def fetchall(self) -> List[Mapping]: ...
-    async def fetchone(self) -> Mapping: ...
-    async def fetchmany(self, size: Optional[Int] = ...) -> List[Mapping]: ...
-    async def all(self) -> List[Mapping]: ...
-    def __aiter__(self): ...
-    async def __anext__(self): ...
-    async def first(self) -> Optional[Mapping]: ...
-    async def one_or_none(self) -> Optional[Mapping]: ...
-    async def one(self) -> Mapping: ...
+        self, size: Optional[int] = ...
+    ) -> Iterator[List[Mapping[Any, Any]]]: ...
+    async def fetchall(self) -> List[Mapping[Any, Any]]: ...
+    async def fetchone(self) -> Optional[Mapping[Any, Any]]: ...
+    async def fetchmany(
+        self, size: Optional[int] = ...
+    ) -> List[Mapping[Any, Any]]: ...
+    async def all(self) -> List[Mapping[Any, Any]]: ...
+    def __aiter__(self: _TAsyncMappingResult) -> _TAsyncMappingResult: ...
+    async def __anext__(self) -> Mapping[Any, Any]: ...
+    async def first(self) -> Optional[Mapping[Any, Any]]: ...
+    async def one_or_none(self) -> Optional[Mapping[Any, Any]]: ...
+    async def one(self) -> Mapping[Any, Any]: ...