Remove pep484 type comments from the code

Current effort is around the stub package, and having typing in
two places makes thing worse, since the types here are usually
outdated compared to the version in the stubs.

Once v2 gets under way we can start consolidating the types
here.

Fixes: #6461

Change-Id: I7132a444bd7138123074bf5bc664b4bb119a85ce

4 files changed, 41 insertions, 117 deletions

diff --git a/lib/sqlalchemy/ext/asyncio/base.py b/lib/sqlalchemy/ext/asyncio/base.py
index d11b059fd..76a2fbbde 100644
--- a/lib/sqlalchemy/ext/asyncio/base.py
+++ b/lib/sqlalchemy/ext/asyncio/base.py
@@ -5,7 +5,7 @@ from . import exc as async_exc
 
 class StartableContext(abc.ABC):
     @abc.abstractmethod
-    async def start(self, is_ctxmanager=False) -> "StartableContext":
+    async def start(self, is_ctxmanager=False):
         pass
 
     def __await__(self):
diff --git a/lib/sqlalchemy/ext/asyncio/engine.py b/lib/sqlalchemy/ext/asyncio/engine.py
index 17ddb614a..9cd3cb2f8 100644
--- a/lib/sqlalchemy/ext/asyncio/engine.py
+++ b/lib/sqlalchemy/ext/asyncio/engine.py
@@ -4,12 +4,6 @@
 #
 # This module is part of SQLAlchemy and is released under
 # the MIT License: http://www.opensource.org/licenses/mit-license.php
-
-from typing import Any
-from typing import Callable
-from typing import Mapping
-from typing import Optional
-
 from . import exc as async_exc
 from .base import ProxyComparable
 from .base import StartableContext
@@ -17,11 +11,8 @@ from .result import AsyncResult
 from ... import exc
 from ... import util
 from ...engine import create_engine as _create_engine
-from ...engine import Result
-from ...engine import Transaction
 from ...future import Connection
 from ...future import Engine
-from ...sql import Executable
 from ...util.concurrency import greenlet_spawn
 
 
@@ -92,11 +83,7 @@ class AsyncConnection(ProxyComparable, StartableContext, AsyncConnectable):
         "sync_connection",
     )
 
-    def __init__(
-        self,
-        async_engine: "AsyncEngine",
-        sync_connection: Optional[Connection] = None,
-    ):
+    def __init__(self, async_engine, sync_connection=None):
         self.engine = async_engine
         self.sync_engine = async_engine.sync_engine
         self.sync_connection = sync_connection
@@ -162,12 +149,12 @@ class AsyncConnection(ProxyComparable, StartableContext, AsyncConnectable):
             self._raise_for_not_started()
         return self.sync_connection
 
-    def begin(self) -> "AsyncTransaction":
+    def begin(self):
         """Begin a transaction prior to autobegin occurring."""
         self._sync_connection()
         return AsyncTransaction(self)
 
-    def begin_nested(self) -> "AsyncTransaction":
+    def begin_nested(self):
         """Begin a nested transaction and return a transaction handle."""
         self._sync_connection()
         return AsyncTransaction(self, nested=True)
@@ -316,10 +303,10 @@ class AsyncConnection(ProxyComparable, StartableContext, AsyncConnectable):
 
     async def exec_driver_sql(
         self,
-        statement: Executable,
-        parameters: Optional[Mapping] = None,
-        execution_options: Mapping = util.EMPTY_DICT,
-    ) -> Result:
+        statement,
+        parameters=None,
+        execution_options=util.EMPTY_DICT,
+    ):
         r"""Executes a driver-level SQL string and return buffered
         :class:`_engine.Result`.
 
@@ -346,10 +333,10 @@ class AsyncConnection(ProxyComparable, StartableContext, AsyncConnectable):
 
     async def stream(
         self,
-        statement: Executable,
-        parameters: Optional[Mapping] = None,
-        execution_options: Mapping = util.EMPTY_DICT,
-    ) -> AsyncResult:
+        statement,
+        parameters=None,
+        execution_options=util.EMPTY_DICT,
+    ):
         """Execute a statement and return a streaming
         :class:`_asyncio.AsyncResult` object."""
 
@@ -371,10 +358,10 @@ class AsyncConnection(ProxyComparable, StartableContext, AsyncConnectable):
 
     async def execute(
         self,
-        statement: Executable,
-        parameters: Optional[Mapping] = None,
-        execution_options: Mapping = util.EMPTY_DICT,
-    ) -> Result:
+        statement,
+        parameters=None,
+        execution_options=util.EMPTY_DICT,
+    ):
         r"""Executes a SQL statement construct and return a buffered
         :class:`_engine.Result`.
 
@@ -426,10 +413,10 @@ class AsyncConnection(ProxyComparable, StartableContext, AsyncConnectable):
 
     async def scalar(
         self,
-        statement: Executable,
-        parameters: Optional[Mapping] = None,
-        execution_options: Mapping = util.EMPTY_DICT,
-    ) -> Any:
+        statement,
+        parameters=None,
+        execution_options=util.EMPTY_DICT,
+    ):
         r"""Executes a SQL statement construct and returns a scalar object.
 
         This method is shorthand for invoking the
@@ -443,7 +430,7 @@ class AsyncConnection(ProxyComparable, StartableContext, AsyncConnectable):
         result = await self.execute(statement, parameters, execution_options)
         return result.scalar()
 
-    async def run_sync(self, fn: Callable, *arg, **kw) -> Any:
+    async def run_sync(self, fn, *arg, **kw):
         """Invoke the given sync callable passing self as the first argument.
 
         This method maintains the asyncio event loop all the way through
@@ -529,7 +516,7 @@ class AsyncEngine(ProxyComparable, AsyncConnectable):
             await self.transaction.__aexit__(type_, value, traceback)
             await self.conn.close()
 
-    def __init__(self, sync_engine: Engine):
+    def __init__(self, sync_engine):
         if not sync_engine.dialect.is_async:
             raise exc.InvalidRequestError(
                 "The asyncio extension requires an async driver to be used. "
@@ -555,7 +542,7 @@ class AsyncEngine(ProxyComparable, AsyncConnectable):
         conn = self.connect()
         return self._trans_ctx(conn)
 
-    def connect(self) -> AsyncConnection:
+    def connect(self):
         """Return an :class:`_asyncio.AsyncConnection` object.
 
         The :class:`_asyncio.AsyncConnection` will procure a database
@@ -573,7 +560,7 @@ class AsyncEngine(ProxyComparable, AsyncConnectable):
 
         return self._connection_cls(self)
 
-    async def raw_connection(self) -> Any:
+    async def raw_connection(self):
         """Return a "raw" DBAPI connection from the connection pool.
 
         .. seealso::
@@ -617,17 +604,14 @@ class AsyncTransaction(ProxyComparable, StartableContext):
 
     __slots__ = ("connection", "sync_transaction", "nested")
 
-    def __init__(self, connection: AsyncConnection, nested: bool = False):
+    def __init__(self, connection, nested=False):
         self.connection = connection
-        self.sync_transaction: Optional[Transaction] = None
+        self.sync_transaction = None
         self.nested = nested
 
     @classmethod
     def _from_existing_transaction(
-        cls,
-        connection: AsyncConnection,
-        sync_transaction: Transaction,
-        nested: bool = False,
+        cls, connection, sync_transaction, nested=False
     ):
         obj = cls.__new__(cls)
         obj.connection = connection
@@ -645,11 +629,11 @@ class AsyncTransaction(ProxyComparable, StartableContext):
         return self.sync_transaction
 
     @property
-    def is_valid(self) -> bool:
+    def is_valid(self):
         return self._sync_transaction().is_valid
 
     @property
-    def is_active(self) -> bool:
+    def is_active(self):
         return self._sync_transaction().is_active
 
     async def close(self):
diff --git a/lib/sqlalchemy/ext/asyncio/result.py b/lib/sqlalchemy/ext/asyncio/result.py
index 6899fe0a6..4781b3ead 100644
--- a/lib/sqlalchemy/ext/asyncio/result.py
+++ b/lib/sqlalchemy/ext/asyncio/result.py
@@ -7,23 +7,12 @@
 
 import operator
 
-from ... import util
 from ...engine.result import _NO_ROW
 from ...engine.result import FilterResult
 from ...engine.result import FrozenResult
 from ...engine.result import MergedResult
 from ...util.concurrency import greenlet_spawn
 
-if util.TYPE_CHECKING:
-    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 ...engine.result import Row
-
 
 class AsyncCommon(FilterResult):
     async def close(self):
@@ -77,7 +66,6 @@ class AsyncResult(AsyncCommon):
         return self
 
     def columns(self, *col_expressions):
-        # type: (*object) -> AsyncResult
         r"""Establish the columns that should be returned in each row.
 
         Refer to :meth:`_engine.Result.columns` in the synchronous
@@ -88,7 +76,6 @@ class AsyncResult(AsyncCommon):
         return self._column_slices(col_expressions)
 
     async def partitions(self, size=None):
-        # type: (Optional[Int]) -> Iterator[List[Any]]
         """Iterate through sub-lists of rows of the size given.
 
         An async iterator is returned::
@@ -115,7 +102,6 @@ class AsyncResult(AsyncCommon):
                 break
 
     async def fetchone(self):
-        # type: () -> Row
         """Fetch one row.
 
         When all rows are exhausted, returns None.
@@ -138,7 +124,6 @@ class AsyncResult(AsyncCommon):
             return row
 
     async def fetchmany(self, size=None):
-        # type: (Optional[Int]) -> List[Row]
         """Fetch many rows.
 
         When all rows are exhausted, returns an empty list.
@@ -160,7 +145,6 @@ class AsyncResult(AsyncCommon):
         return await greenlet_spawn(self._manyrow_getter, self, size)
 
     async def all(self):
-        # type: () -> List[Row]
         """Return all rows in a list.
 
         Closes the result set after invocation.   Subsequent invocations
@@ -183,7 +167,6 @@ class AsyncResult(AsyncCommon):
             return row
 
     async def first(self):
-        # type: () -> Row
         """Fetch the first row or None if no row is present.
 
         Closes the result set and discards remaining rows.
@@ -207,7 +190,6 @@ class AsyncResult(AsyncCommon):
         return await greenlet_spawn(self._only_one_row, False, False, False)
 
     async def one_or_none(self):
-        # type: () -> Optional[Row]
         """Return at most one result or raise an exception.
 
         Returns ``None`` if the result has no rows.
@@ -230,7 +212,6 @@ class AsyncResult(AsyncCommon):
         return await greenlet_spawn(self._only_one_row, True, False, False)
 
     async def scalar_one(self):
-        # type: () -> Any
         """Return exactly one scalar result or raise an exception.
 
         This is equivalent to calling :meth:`_asyncio.AsyncResult.scalars` and
@@ -246,7 +227,6 @@ class AsyncResult(AsyncCommon):
         return await greenlet_spawn(self._only_one_row, True, True, True)
 
     async def scalar_one_or_none(self):
-        # type: () -> Optional[Any]
         """Return exactly one or no scalar result.
 
         This is equivalent to calling :meth:`_asyncio.AsyncResult.scalars` and
@@ -262,7 +242,6 @@ class AsyncResult(AsyncCommon):
         return await greenlet_spawn(self._only_one_row, True, False, True)
 
     async def one(self):
-        # type: () -> Row
         """Return exactly one row or raise an exception.
 
         Raises :class:`.NoResultFound` if the result returns no
@@ -294,7 +273,6 @@ class AsyncResult(AsyncCommon):
         return await greenlet_spawn(self._only_one_row, True, True, False)
 
     async def scalar(self):
-        # type: () -> Optional[Any]
         """Fetch the first column of the first row, and close the result set.
 
         Returns None if there are no rows to fetch.
@@ -350,7 +328,6 @@ class AsyncResult(AsyncCommon):
         return MergedResult(self._metadata, (self,) + others)
 
     def scalars(self, index=0):
-        # type: (Int) -> AsyncScalarResult
         """Return an :class:`_asyncio.AsyncScalarResult` filtering object which
         will return single elements rather than :class:`_row.Row` objects.
 
@@ -367,7 +344,6 @@ class AsyncResult(AsyncCommon):
         return AsyncScalarResult(self._real_result, index)
 
     def mappings(self):
-        # type() -> AsyncMappingResult
         """Apply a mappings filter to returned rows, returning an instance of
         :class:`_asyncio.AsyncMappingResult`.
 
@@ -414,7 +390,6 @@ class AsyncScalarResult(AsyncCommon):
         self._unique_filter_state = real_result._unique_filter_state
 
     def unique(self, strategy=None):
-        # type: () -> AsyncScalarResult
         """Apply unique filtering to the objects returned by this
         :class:`_asyncio.AsyncScalarResult`.
 
@@ -425,7 +400,6 @@ class AsyncScalarResult(AsyncCommon):
         return self
 
     async def partitions(self, size=None):
-        # type: (Optional[Int]) -> Iterator[List[Any]]
         """Iterate through sub-lists of elements of the size given.
 
         Equivalent to :meth:`_asyncio.AsyncResult.partitions` except that
@@ -444,13 +418,11 @@ class AsyncScalarResult(AsyncCommon):
                 break
 
     async def fetchall(self):
-        # type: () -> List[Any]
         """A synonym for the :meth:`_asyncio.AsyncScalarResult.all` method."""
 
         return await greenlet_spawn(self._allrows)
 
     async def fetchmany(self, size=None):
-        # type: (Optional[Int]) -> List[Any]
         """Fetch many objects.
 
         Equivalent to :meth:`_asyncio.AsyncResult.fetchmany` except that
@@ -461,7 +433,6 @@ class AsyncScalarResult(AsyncCommon):
         return await greenlet_spawn(self._manyrow_getter, self, size)
 
     async def all(self):
-        # type: () -> List[Any]
         """Return all scalar values in a list.
 
         Equivalent to :meth:`_asyncio.AsyncResult.all` except that
@@ -482,7 +453,6 @@ class AsyncScalarResult(AsyncCommon):
             return row
 
     async def first(self):
-        # type: () -> Optional[Any]
         """Fetch the first object or None if no object is present.
 
         Equivalent to :meth:`_asyncio.AsyncResult.first` except that
@@ -493,7 +463,6 @@ class AsyncScalarResult(AsyncCommon):
         return await greenlet_spawn(self._only_one_row, False, False, False)
 
     async def one_or_none(self):
-        # type: () -> Optional[Any]
         """Return at most one object or raise an exception.
 
         Equivalent to :meth:`_asyncio.AsyncResult.one_or_none` except that
@@ -504,7 +473,6 @@ class AsyncScalarResult(AsyncCommon):
         return await greenlet_spawn(self._only_one_row, True, False, False)
 
     async def one(self):
-        # type: () -> Any
         """Return exactly one object or raise an exception.
 
         Equivalent to :meth:`_asyncio.AsyncResult.one` except that
@@ -556,7 +524,6 @@ class AsyncMappingResult(AsyncCommon):
         return self._metadata.keys
 
     def unique(self, strategy=None):
-        # type: () -> AsyncMappingResult
         """Apply unique filtering to the objects returned by this
         :class:`_asyncio.AsyncMappingResult`.
 
@@ -567,12 +534,10 @@ class AsyncMappingResult(AsyncCommon):
         return self
 
     def columns(self, *col_expressions):
-        # type: (*object) -> AsyncMappingResult
         r"""Establish the columns that should be returned in each row."""
         return self._column_slices(col_expressions)
 
     async def partitions(self, size=None):
-        # type: (Optional[Int]) -> Iterator[List[Mapping]]
         """Iterate through sub-lists of elements of the size given.
 
         Equivalent to :meth:`_asyncio.AsyncResult.partitions` except that
@@ -591,13 +556,11 @@ class AsyncMappingResult(AsyncCommon):
                 break
 
     async def fetchall(self):
-        # type: () -> List[Mapping]
         """A synonym for the :meth:`_asyncio.AsyncMappingResult.all` method."""
 
         return await greenlet_spawn(self._allrows)
 
     async def fetchone(self):
-        # type: () -> Mapping
         """Fetch one object.
 
         Equivalent to :meth:`_asyncio.AsyncResult.fetchone` except that
@@ -613,7 +576,6 @@ class AsyncMappingResult(AsyncCommon):
             return row
 
     async def fetchmany(self, size=None):
-        # type: (Optional[Int]) -> List[Mapping]
         """Fetch many objects.
 
         Equivalent to :meth:`_asyncio.AsyncResult.fetchmany` except that
@@ -625,7 +587,6 @@ class AsyncMappingResult(AsyncCommon):
         return await greenlet_spawn(self._manyrow_getter, self, size)
 
     async def all(self):
-        # type: () -> List[Mapping]
         """Return all scalar values in a list.
 
         Equivalent to :meth:`_asyncio.AsyncResult.all` except that
@@ -647,7 +608,6 @@ class AsyncMappingResult(AsyncCommon):
             return row
 
     async def first(self):
-        # type: () -> Optional[Mapping]
         """Fetch the first object or None if no object is present.
 
         Equivalent to :meth:`_asyncio.AsyncResult.first` except that
@@ -659,7 +619,6 @@ class AsyncMappingResult(AsyncCommon):
         return await greenlet_spawn(self._only_one_row, False, False, False)
 
     async def one_or_none(self):
-        # type: () -> Optional[Mapping]
         """Return at most one object or raise an exception.
 
         Equivalent to :meth:`_asyncio.AsyncResult.one_or_none` except that
@@ -670,7 +629,6 @@ class AsyncMappingResult(AsyncCommon):
         return await greenlet_spawn(self._only_one_row, True, False, False)
 
     async def one(self):
-        # type: () -> Mapping
         """Return exactly one object or raise an exception.
 
         Equivalent to :meth:`_asyncio.AsyncResult.one` except that
diff --git a/lib/sqlalchemy/ext/asyncio/session.py b/lib/sqlalchemy/ext/asyncio/session.py
index 1b61d6ee3..8d19819b0 100644
--- a/lib/sqlalchemy/ext/asyncio/session.py
+++ b/lib/sqlalchemy/ext/asyncio/session.py
@@ -4,27 +4,14 @@
 #
 # This module is part of SQLAlchemy and is released under
 # the MIT License: http://www.opensource.org/licenses/mit-license.php
-
-from typing import Any
-from typing import Callable
-from typing import Mapping
-from typing import Optional
-from typing import TypeVar
-
 from . import engine
 from . import result as _result
 from .base import StartableContext
-from .engine import AsyncEngine
 from ... import util
-from ...engine import Result
 from ...orm import Session
-from ...sql import Executable
 from ...util.concurrency import greenlet_spawn
 
 
-T = TypeVar("T")
-
-
 @util.create_proxy_methods(
     Session,
     ":class:`_orm.Session`",
@@ -72,12 +59,7 @@ class AsyncSession:
 
     dispatch = None
 
-    def __init__(
-        self,
-        bind: AsyncEngine = None,
-        binds: Mapping[object, AsyncEngine] = None,
-        **kw
-    ):
+    def __init__(self, bind=None, binds=None, **kw):
         kw["future"] = True
         if bind:
             self.bind = bind
@@ -114,7 +96,7 @@ class AsyncSession:
             with_for_update=with_for_update,
         )
 
-    async def run_sync(self, fn: Callable[..., T], *arg, **kw) -> T:
+    async def run_sync(self, fn, *arg, **kw):
         """Invoke the given sync callable passing sync self as the first
         argument.
 
@@ -143,12 +125,12 @@ class AsyncSession:
 
     async def execute(
         self,
-        statement: Executable,
-        params: Optional[Mapping] = None,
-        execution_options: Mapping = util.EMPTY_DICT,
-        bind_arguments: Optional[Mapping] = None,
+        statement,
+        params=None,
+        execution_options=util.EMPTY_DICT,
+        bind_arguments=None,
         **kw
-    ) -> Result:
+    ):
         """Execute a statement and return a buffered
         :class:`_engine.Result` object."""
 
@@ -165,12 +147,12 @@ class AsyncSession:
 
     async def scalar(
         self,
-        statement: Executable,
-        params: Optional[Mapping] = None,
-        execution_options: Mapping = util.EMPTY_DICT,
-        bind_arguments: Optional[Mapping] = None,
+        statement,
+        params=None,
+        execution_options=util.EMPTY_DICT,
+        bind_arguments=None,
         **kw
-    ) -> Any:
+    ):
         """Execute a statement and return a scalar result."""
 
         result = await self.execute(