def record_from_current_or_find(klass, id, current)
      if current.is_a?(ActiveRecord::Base) && current.id.to_s == id
        # modifying the current object of a singular association
        current
      elsif current.respond_to?(:any?) && current.any? { |o| o.id.to_s == id }
        # modifying one of the current objects in a plural association
        current.detect { |o| o.id.to_s == id }
      else # attaching an existing but not-current object
        klass.find(id)
      end
    end
def record_from_current_or_find(klass, id, current)
      if current.is_a?(ActiveRecord::Base) && current.id.to_s == id
        # modifying the current object of a singular association
        current
      elsif current.respond_to?(:any?) && current.any? { |o| o.id.to_s == id }
        # modifying one of the current objects in a plural association
        current.detect { |o| o.id.to_s == id }
      else # attaching an existing but not-current object
        klass.find(id)
      end
    end
Attempts to find an instance of klass (which must be an ActiveRecord object) with id primary key
 Returns record from current if it's included or find from DB