fn do_flatten_object(
dest: &mut PipelineMap,
base: Option<&str>,
object: PipelineMap,
current_level: usize,
max_nested_levels: usize,
) -> Result<()>
fn do_flatten_object(
dest: &mut PipelineMap,
base: Option<&str>,
object: PipelineMap,
current_level: usize,
max_nested_levels: usize,
) -> Result<()>