Documentation: YouTube video URL has a bad parameter value

[prafullkotecha]

See the code segment in this section.
The YouTube video URL points to a video, v=_aGCpUeIVZ4.
This causes following error while trying to store the document in cloudant db.

_aGCpUeIVZ4 - failed to write to DB { Error: Only reserved document ids may start with underscore.
    at Request._callback (/Users/prafulll/code/personal/direkshanProjects/ibm-dw/watson-multimedia-analyzer/node_modules/cloudant-nano/lib/nano.js:248:15)
    at Request.self.callback (/Users/prafulll/code/personal/direkshanProjects/ibm-dw/watson-multimedia-analyzer/node_modules/request/request.js:186:22)
    at Request.emit (events.js:160:13)
    at Request.<anonymous> (/Users/prafulll/code/personal/direkshanProjects/ibm-dw/watson-multimedia-analyzer/node_modules/request/request.js:1163:10)
    at Request.emit (events.js:160:13)
    at IncomingMessage.<anonymous> (/Users/prafulll/code/personal/direkshanProjects/ibm-dw/watson-multimedia-analyzer/node_modules/request/request.js:1085:12)
    at Object.onceWrapper (events.js:255:19)
    at IncomingMessage.emit (events.js:165:20)
    at endReadableNT (_stream_readable.js:1101:12)
    at process._tickCallback (internal/process/next_tick.js:152:19)
  name: 'Error',
  error: 'illegal_docid',
  reason: 'Only reserved document ids may start with underscore.',
  scope: 'couch',
  statusCode: 400,
...