---
author: NN
css: mkdoc.css
date: 2023-12-19
title: Documentation cap-999999.0a1.0
---
> concepts:
> A capability may be something like providing a folder of files, or just a data dictionary, and/or an API 

> capability handler - a package/namespace which may provide validation and standardised ways of looking up provider data
  registered (or not) using register_capabilityname <capname> <capnamespace>

> capability provider - a package which registers as providing one or more capablities.
 registered using register_package <pkg> <capabilitylist>
 the capabilitylist is a list of 2-element lists where the first element is the capabilityname and the second element is a (possibly empty) dict of data relevant to that capability
 A capabilityname may appear multiple times. ie a package may register that it provides the capability with multiple datasets.

## **exists(capname)**

> return a boolean indicating the existence of a capability

> Arguments:

> - *capname* - string indicating the name of the capability

> Returns: 0|1