• They can be passed in as arguments, or returned from functions.
• Only basic types and python objects can occur in tuples
  • No nesting
  • No options
• You can stick tuples inside a List, Seq, or Array, e.g., (int * string) list, but not in option or Or_error.t.
• If you break these rules, you will get runtime errors :)

See the dune file for auto-generating the bindings. If you don't want to use Dune rules for this, you can still use the rule as an example of how to run pyml_bindgen manually.