ruby - What is the best way to assign nil to a default association? -

so if have factory such (address factory) , want create test creates person no address

require 'faker'  factorygirl.define   factory :person     address     first        { faker::name.first_name }     last         { faker::name.last_name }   end end 

i expect following work (but doesn't):

create(:person, address: nil)

what best way set properly?