Prefer this ES source or producer. The argument can either be an object label, e.g., process.prefer(process.juicerProducer) (not supported yet) or a name of an ESSource or ESProducer process.prefer("juicer") or a type of unnamed ESSource or
(self, esmodule,*args,**kargs)
source not stored for this graph (policy: none)
no test coverage detected