UI Module Function.
Arguments
- id
 A string. A namespace for the module.
- urn
 A string. Source URN (objectId) for the file. Note the URN must be Base64 encoded. To encode the URN, see, for example, the
jsonlite::base64_encfunction.- token
 A string. Token generated with
getTokenfunction withdata:readscope.- viewerType
 A string. The type of viewer to instantiate. Either "header" for the default viewer or "headless" for a viewer without toolbar or panels.