Driver.Instrumentval make : 
  (Ppxlib_ast.Parsetree.structure -> Ppxlib_ast.Parsetree.structure) ->
  position:pos ->
  tmake transformation ~position creates an instrumentation that can be passed to Driver.register_transformation to instrument an implementation file. transformation is the transformation that will be applied to the AST; position specifies if it should be applied before or after rewriters defined through rules, impl or intf are applied.
module V2 : sig ... end