{{< tip title="Download the '.zip' file and install the reusable code that the 'date-time' major section describes and uses." >}}

Each of these five sections describes reusable code that you might find useful:

- [User-defined _interval_ utility functions](../date-time-data-types-semantics/type-interval/interval-utilities/)
- [Modeling the internal representation and comparing the model with the actual implementation](../date-time-data-types-semantics/type-interval/interval-representation/internal-representation-model/)
- [Custom domain types for specializing the native _interval_ functionality](../date-time-data-types-semantics/type-interval/custom-interval-domains/)
- [The _extended_timezone_names view_](../timezones/extended-timezone-names/)
- [Recommended practice for specifying the _UTC offset_](../timezones/recommendation/)
- [Rules for resolving a string that's intended to identify a _UTC offset  > Helper functions](../timezones/ways-to-spec-offset/name-res-rules/helper-functions/)

Moreover, some of the code examples depend on some of this code. Yugabyte recommends therefore that you download and install the entire kit into the database that you use to support your study of the _date-time_ data types. With this code installed, all the code examples on every page listed in the [Table of contents](../toc/) will run without error provided only that, in the general case, you run them in the order in which a particular page presents them.

[Download date-time-utilities.zip](https://raw.githubusercontent.com/yugabyte/yugabyte-db/master/sample/date-time-utilities/date-time-utilities.zip) to any convenient directory and unzip it. It creates a small directory hierarchy.

You'll find _README.pdf_ at the top level. It describes the rest of the content and tells you simply to start the master script _0.sql_ at the _ysqlsh_ prompt (or at the _psql_ prompt). You can run it time and again. It will always finish silently.
{{< /tip >}}