p:validate-with-xml-schema question

Section 7.2.6 (p:validate-with-xml-schema) says:

"It is a dynamic error (err:XC0053) if the assert-valid option is true
and the input document is not valid."

But what happens if assert-valid=false and the document is not valid?
The step then just returns the input document, behaving like p:identity?

Regards,
Vojtech