In the article they mentioned they implemented custom type system for building UI and for the input&#x2F;output. Interesting, but I don&#x27;t understand what that means. Are we talking about data type? Custom compiler? Very very elegant ideas I supposed, but I am just not familiar with the concepts...<p>&gt; The body of the workflow looks like a normal Python function with calls to several operators, which do the real machine learning work. Despite its normal appearances, FBLearner Flow employs a system of futures to provide parallelization within the workflow, allowing steps that do not share a data dependency to run simultaneously.<p>&quot;Futures&quot; did they implement this with concurrent.futures (which also has a backport prior to Ptyhon 3.2)?