Email alert condition null value fields

I want to send an email notification each time a user enters a comment for a quotation.
I created a new email alert for the document type Commmunication with the following condition:
(Doc.content! = ‘None’ or doc.subject! = ‘None’) and doc.reference_doctype == ‘Quotation’

but the field verification and doc.content doc.subject not work.
Is sent to the email even if the fields are with value ‘None’
How can I check the null value of a field?


@enriweb77 just

(doc.content != None or doc.subject != None) and doc.reference_doctype == "Quotation"

I try now, thanks!

Work fine!! Thanks