--sort option fails on bf luis:convert

[scheyal]

Versions

c:>bf --version
@microsoft/botframework-cli/4.11.1 win32-x64 node-v12.18.4

Describe the bug

Run the bf luis:convert ... --sort command and get a failure. Same command works without --sort.

To Reproduce

>bf luis:convert --in test.json --out test.lu --sort
Unknown error during execution. Please file an issue on https://github.com/microsoft/botframework-cli/issues
Cannot read property 'sort' of undefined

>bf luis:convert --help
Convert .lu file(s) to a LUIS application JSON model or vice versa
 
USAGE
  $ bf luis:convert
 
OPTIONS
  -f, --force                    If --out flag is provided with the path to an existing file, overwrites that file
  -h, --help                     luis:convert help
  -i, --in=in                    Source .lu file(s) or LUIS application JSON model
  -o, --out=out                  Output file or folder name. If not specified stdout will be used as output
  -r, --recurse                  Indicates if sub-folders need to be considered to file .lu file(s)
  --culture=culture              Lang code for the LUIS application
  --description=description      Text describing the LUIS applicaion
  --log                          Enables log messages
  --name=name                    Name of the LUIS application
  --schemaversion=schemaversion  Schema version of the LUIS application
  --sort                         When set, intent, utterances, entities are alphabetically sorted in .lu files
  --versionid=versionid          Version ID of the LUIS application

Expected behavior

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[bug]