Build query to exclude category

[infogulch]

I'm trying to build this query:

not categories/any(a: a eq 'Green category')

This

query = self.mailbox.new_query()
query = query.negate(query.any("categories", query.equals("category", "Green category")))

But this builds the query not categories/any(a: a/category eq 'Green category') which gives an error Error Message: Invalid filter clause: Could not find a property named 'category' on type 'Edm.String'.

How can I use the query builder to build the above query?