reduce from 3 to 2 packages

src/nominatim_api/typing.py

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+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+# This file is part of Nominatim. (https://nominatim.org)
+#
+# Copyright (C) 2024 by the Nominatim developer community.
+# For a full list of authors see the git log.
+"""
+Type definitions for typing annotations.
+
+Complex type definitions are moved here, to keep the source files readable.
+"""
+from typing import Union, TYPE_CHECKING
+
+# pylint: disable=missing-class-docstring,useless-import-alias
+
+# SQLAlchemy introduced generic types in version 2.0 making typing
+# incompatible with older versions. Add wrappers here so we don't have
+# to litter the code with bare-string types.
+
+if TYPE_CHECKING:
+    from typing import Any
+    import sqlalchemy as sa
+    import os
+    from typing_extensions import (TypeAlias as TypeAlias)
+else:
+    TypeAlias = str
+
+StrPath = Union[str, 'os.PathLike[str]']
+
+SaLambdaSelect: TypeAlias = 'Union[sa.Select[Any], sa.StatementLambdaElement]'
+SaSelect: TypeAlias = 'sa.Select[Any]'
+SaScalarSelect: TypeAlias = 'sa.ScalarSelect[Any]'
+SaRow: TypeAlias = 'sa.Row[Any]'
+SaColumn: TypeAlias = 'sa.ColumnElement[Any]'
+SaExpression: TypeAlias = 'sa.ColumnElement[bool]'
+SaLabel: TypeAlias = 'sa.Label[Any]'
+SaFromClause: TypeAlias = 'sa.FromClause'
+SaSelectable: TypeAlias = 'sa.Selectable'
+SaBind: TypeAlias = 'sa.BindParameter[Any]'
+SaDialect: TypeAlias = 'sa.Dialect'