Wendelin provides the getData API which can be used on any Data Stream
object stored in Wendelin. The API is described in detail in How To Use getData API (coming soon)
which also provides several examples.
Fur further reading you could also directly access examples through the ERP5 Zope
Interface. These can either be found on an installed instance of Wendelin by
heading to the ERP5 Zope interface at ./portal_skins/erp5_wendelin_examples
(make sure the URL is relative to the root of your wendelin instance) or accessing
the same file on the Wendelin Gitlab Repository.