pub fn from_lambda_variable(
producer: &mut impl SubstraitProducer,
lambda_variable: &LambdaVariable,
_schema: &DFSchema,
) -> Result<Expression, DataFusionError>pub fn from_lambda_variable(
producer: &mut impl SubstraitProducer,
lambda_variable: &LambdaVariable,
_schema: &DFSchema,
) -> Result<Expression, DataFusionError>