async fn derive_writes(
conn: &mut PgConnection,
view: &CourseView,
after: &CourseState,
source: WriteSource,
) -> Result<DerivedWrites, ToolError>async fn derive_writes(
conn: &mut PgConnection,
view: &CourseView,
after: &CourseState,
source: WriteSource,
) -> Result<DerivedWrites, ToolError>