find

# File activerecord/lib/active_record/migration/compatibility.rb, line 6
      def self.find(version)
        version = version.to_s
        name = "V#{version.tr('.', '_')}"
        unless const_defined?(name)
          versions = constants.grep(/\AV[0-9_]+\z/).map { |s| s.to_s.delete("V").tr("_", ".").inspect }
          raise ArgumentError, "Unknown migration version #{version.inspect}; expected one of #{versions.sort.join(', ')}"
        end
        const_get(name)
      end