# File lib/json-schema/validator.rb, line 372
      def register_format_validator(format, validation_proc, versions = ["draft1", "draft2", "draft3", "draft4", nil])
        custom_format_validator = JSON::Schema::CustomFormat.new(validation_proc)
        validators_for_names(versions).each do |validator|
          validator.formats[format.to_s] = custom_format_validator
        end
      end