from __future__ import annotations from typing import TYPE_CHECKING, Any, TypeVar if TYPE_CHECKING: from narwhals._sql.dataframe import SQLLazyFrame from narwhals._sql.expr import SQLExpr SQLExprAny = SQLExpr[Any, Any] SQLLazyFrameAny = SQLLazyFrame[Any, Any, Any] SQLExprT = TypeVar("SQLExprT", bound="SQLExprAny") SQLExprT_contra = TypeVar("SQLExprT_contra", bound="SQLExprAny", contravariant=True) SQLLazyFrameT = TypeVar("SQLLazyFrameT", bound="SQLLazyFrameAny")