# File lib/mongoid/relations/bindings/referenced/many_to_many.rb, line 36
          def unbind_one(doc)
            unless _binding?
              _binding do
                base.send(metadata.foreign_key).delete_one(doc.id)
                inverse_keys = doc.you_must(metadata.inverse_foreign_key)
                inverse_keys.delete_one(base.id) if inverse_keys
                base.synced[metadata.foreign_key] = true
                doc.synced[metadata.inverse_foreign_key] = true
              end
            end
          end