Fix linting issues

alembic/ddl/impl.py

@@ -48,11 +48,9 @@
     from sqlalchemy.sql import Executable
     from sqlalchemy.sql.elements import ColumnElement
     from sqlalchemy.sql.elements import quoted_name
-    from sqlalchemy.sql.schema import Column
     from sqlalchemy.sql.schema import Constraint
     from sqlalchemy.sql.schema import ForeignKeyConstraint
     from sqlalchemy.sql.schema import Index
-    from sqlalchemy.sql.schema import Table
     from sqlalchemy.sql.schema import UniqueConstraint
     from sqlalchemy.sql.selectable import TableClause
     from sqlalchemy.sql.type_api import TypeEngine
@@ -141,7 +139,9 @@ def static_output(self, text: str) -> None:
         self.output_buffer.write(text + "\n\n")
         self.output_buffer.flush()
 
-    def version_table_impl(self, version_table, version_table_schema, version_table_pk):
+    def version_table_impl(
+        self, version_table, version_table_schema, version_table_pk
+    ) -> Table:
         """create the Table object for the version_table.
 
         Provided as part of impl so that third party dialects can override

alembic/runtime/migration.py

@@ -24,7 +24,6 @@
 
 from sqlalchemy import Column
 from sqlalchemy import literal_column
-from sqlalchemy import select
 from sqlalchemy.engine import Engine
 from sqlalchemy.engine import url as sqla_url
 from sqlalchemy.engine.strategies import MockEngineStrategy
@@ -531,7 +530,9 @@ def get_current_heads(self) -> Tuple[str, ...]:
                 return ()
         assert self.connection is not None
         return tuple(
-            row[0] for row in self.connection.execute(select(self._version.c.version_num))
+            row[0] for row in self.connection.execute(
+                self._version.select().with_only_columns(
+                    self._version.c.version_num))
         )
 
     def _ensure_version_table(self, purge: bool = False) -> None:

tests/test_version_table.py

@@ -23,8 +23,6 @@
 )
 
 
-
-
 def _up(from_, to_, branch_presence_changed=False):
     return migration.StampStep(from_, to_, True, branch_presence_changed)
 
@@ -385,7 +383,9 @@ class CustomVersionTableTest(TestMigrationContext):
 
     class MyDialectImpl(impl.DefaultImpl):
 
-        def version_table_impl(self, version_table, version_table_schema, version_table_pk):
+        def version_table_impl(
+            self, version_table, version_table_schema, version_table_pk
+        ):
             vt = Table(
                 version_table,
                 MetaData(),
@@ -401,9 +401,9 @@ def version_table_impl(self, version_table, version_table_schema, version_table_
                 )
             return vt
 
-
     def setUp(self):
-        # nasty hack to get the sqlite dialect to use our custom dialect implementation
+        # nasty hack to get the sqlite dialect
+        # to use our custom dialect implementation
         impl._impls["sqlite_bak"] = impl._impls["sqlite"]
         impl._impls["sqlite"] = self.MyDialectImpl
         super().setUp()