API refactor

venv/lib/python3.12/site-packages/alembic/templates/generic/script.py.mako

@@ -13,14 +13,16 @@ ${imports if imports else ""}
 
 # revision identifiers, used by Alembic.
 revision: str = ${repr(up_revision)}
-down_revision: Union[str, None] = ${repr(down_revision)}
+down_revision: Union[str, Sequence[str], None] = ${repr(down_revision)}
 branch_labels: Union[str, Sequence[str], None] = ${repr(branch_labels)}
 depends_on: Union[str, Sequence[str], None] = ${repr(depends_on)}
 
 
 def upgrade() -> None:
+    """Upgrade schema."""
     ${upgrades if upgrades else "pass"}
 
 
 def downgrade() -> None:
+    """Downgrade schema."""
     ${downgrades if downgrades else "pass"}