module Bullet::Ext::Object

def bullet_primary_key_value
  return if respond_to?(:persisted?) && !persisted?
  @bullet_primary_key_value ||=
    begin
      primary_key = self.class.try(:primary_keys) || self.class.try(:primary_key) || :id
      bullet_join_potential_composite_primary_key(primary_key)
    end
end