validates_each (ActiveRecord::Validations::ClassMethods)

    # File lib/active_record/validations.rb, line 459
          def validates_each(*attrs)
            options = attrs.extract_options!.symbolize_keys
            attrs   = attrs.flatten

            # Declare the validation.
            send(validation_method(options[:on] || :save), options) do |record|
              attrs.each do |attr|
                value = record.send(attr)
                next if (value.nil? && options[:allow_nil]) || (value.blank? && options[:allow_blank])
                yield record, attr, value
              end
            end
          end