swagger init failed: undefined

I was so excited when I found this CLI tool!
Sadly doesn't seeem to be working. There are errors in installation (though it succeeds) and runtime gets stuck at an error.

```
npm install -g npr-one
npm WARN deprecated swagger-client@2.2.21: No longer maintained, please upgrade to swagger-client@3.
npm WARN deprecated superagent@2.3.0: Please note that v5.0.1+ of superagent removes User-Agent header by default, therefore you may need to add it yourself (e.g. GitHub blocks requests without a User-Agent header). This notice will go away with v5.0.2+ once it is released.
/usr/local/bin/npr-one -> /usr/local/lib/node_modules/npr-one/cli

> dtrace-provider@0.8.8 install /usr/local/lib/node_modules/npr-one/node_modules/dtrace-provider
> node-gyp rebuild || node suppress-error.js

Traceback (most recent call last):
File "/usr/local/lib/node_modules/npm/node_modules/node-gyp/gyp/gyp_main.py", line 50, in
sys.exit(gyp.script_main())
File "/usr/local/lib/node_modules/npm/node_modules/node-gyp/gyp/pylib/gyp/__init__.py", line 554, in script_main
return main(sys.argv[1:])
File "/usr/local/lib/node_modules/npm/node_modules/node-gyp/gyp/pylib/gyp/__init__.py", line 547, in main
return gyp_main(args)
File "/usr/local/lib/node_modules/npm/node_modules/node-gyp/gyp/pylib/gyp/__init__.py", line 532, in gyp_main
generator.GenerateOutput(flat_list, targets, data, params)
File "/usr/local/lib/node_modules/npm/node_modules/node-gyp/gyp/pylib/gyp/generator/make.py", line 2215, in GenerateOutput
part_of_all=qualified_target in needed_targets)
File "/usr/local/lib/node_modules/npm/node_modules/node-gyp/gyp/pylib/gyp/generator/make.py", line 794, in Write
extra_mac_bundle_resources, part_of_all)
File "/usr/local/lib/node_modules/npm/node_modules/node-gyp/gyp/pylib/gyp/generator/make.py", line 900, in WriteActions
env = self.GetSortedXcodeEnv()
File "/usr/local/lib/node_modules/npm/node_modules/node-gyp/gyp/pylib/gyp/generator/make.py", line 1885, in GetSortedXcodeEnv
additional_settings)
File "/usr/local/lib/node_modules/npm/node_modules/node-gyp/gyp/pylib/gyp/xcode_emulation.py", line 1616, in GetSortedXcodeEnv
additional_settings)
File "/usr/local/lib/node_modules/npm/node_modules/node-gyp/gyp/pylib/gyp/xcode_emulation.py", line 1527, in _GetXcodeEnv
if XcodeVersion() >= '0500' and not env.get('SDKROOT'):
TypeError: '>=' not supported between instances of 'tuple' and 'str'
gyp ERR! configure error
gyp ERR! stack Error: `gyp` failed with exit code: 1
gyp ERR! stack at ChildProcess.onCpExit (/usr/local/lib/node_modules/npm/node_modules/node-gyp/lib/configure.js:351:16)
gyp ERR! stack at ChildProcess.emit (events.js:305:20)
gyp ERR! stack at Process.ChildProcess._handle.onexit (internal/child_process.js:275:12)
gyp ERR! System Darwin 19.0.0
gyp ERR! command "/usr/local/Cellar/node/13.5.0/bin/node" "/usr/local/lib/node_modules/npm/node_modules/node-gyp/bin/node-gyp.js" "rebuild"
gyp ERR! cwd /usr/local/lib/node_modules/npr-one/node_modules/dtrace-provider
gyp ERR! node -v v13.5.0
gyp ERR! node-gyp -v v5.0.5
gyp ERR! not ok

> i2c-bus@1.2.5 install /usr/local/lib/node_modules/npr-one/node_modules/i2c-bus
> node-gyp rebuild

SOLINK_MODULE(target) Release/i2c.node
+ npr-one@1.6.1
added 108 packages from 120 contributors in 5.361s
```

```
npr-one

██████████████████████████████████████████████████████████████████████████████
██████████████████████████████████████████████████████████████████████████████
██████████████████████████████████████████████████████████████████████████████
███████▄▄▄▄▄███▄▄████████████████▄▄▄▄▄███▄▄█████████████████▄▄▄▄▄▄████████████
███████████▄▄▄▄███▄██████████████████▄▄▄████▄████████████████████▄▄▄▄█████████
█████████████████████████████████████████▄████████████████████████████████████
███████████████████████████████████████████████████████████████▄██████████████
█████████████████████████████████████████▄████████████████████████████████████
████████████████████████████████████▄▄▄▄████▄█████████████████████████████████
███████▄▄▄██████▄▄▄█████████████████▄███▄▄▄█████████████████▄▄▄▄██████████████
██████████████████████████████████████████████████████████████████████████████
██████████████████████████████████████████████████████████████████████████████
█████████████████████████████████▄▄▄██████████████████████████████████████████
connecting to npr one...
swagger init failed undefined
```

gets stuck here indefinitely.

Start by reproducing the reported failure with the `npr-one` command on the shown Darwin and Node.js setup, then trace the CLI's Swagger initialization. The report includes install logs and the `swagger init failed undefined` output, but names no files or tests. Done means the command no longer gets stuck at that error.

Written by the indexing model from the issue text.