Handle multiple node objects in JSON-LD (was: Generic Extractor: AttributeError: 'list' object has no attribute 'get')

[canavan]

• I've verified and I assure that I'm running youtube-dl 2016.07.30
• At least skimmed through README and most notably FAQ and BUGS sections
• Searched the bugtracker for similar issues including closed ones

What is the purpose of your issue?

- [X] Bug report (encountered problems with youtube-dl)

youtube-dl --verbose https://rumble.com/v31a0x-19-people-who-should-stay-away-from-power-tools.html
[debug] System config: []
[debug] User config: []
[debug] Command-line args: [u'--verbose', u'https://rumble.com/v31a0x-19-people-who-should-stay-away-from-power-tools.html']
[debug] Encodings: locale ISO8859-1, fs ISO8859-1, out ISO8859-1, pref ISO8859-1
[debug] youtube-dl version 2016.07.30
[debug] Python version 2.7.12 - IRIX64-6.5-IP35-mips-n32bit-ELF
[debug] exe versions: ffmpeg UNKNOWN, ffprobe UNKNOWN, rtmpdump 2.2b
[debug] Proxy map: {}
[generic] v31a0x-19-people-who-should-stay-away-from-power-tools: Requesting header
WARNING: Falling back on generic information extractor.
[generic] v31a0x-19-people-who-should-stay-away-from-power-tools: Downloading webpage
[generic] v31a0x-19-people-who-should-stay-away-from-power-tools: Extracting information
Traceback (most recent call last):
File "/usr/nekoware/lib/python2.7/runpy.py", line 174, in _run_module_as_main
"main", fname, loader, pkg_name)
File "/usr/nekoware/lib/python2.7/runpy.py", line 72, in _run_code
exec code in run_globals
File "/usr/nekoware/bin/youtube-dl/main.py", line 19, in
File "/usr/nekoware/bin/youtube-dl/youtube_dl/init.py", line 422, in main
File "/usr/nekoware/bin/youtube-dl/youtube_dl/init.py", line 412, in _real_main
File "/usr/nekoware/bin/youtube-dl/youtube_dl/YoutubeDL.py", line 1775, in download
File "/usr/nekoware/bin/youtube-dl/youtube_dl/YoutubeDL.py", line 682, in extract_info
File "/usr/nekoware/bin/youtube-dl/youtube_dl/extractor/common.py", line 347, in extract
File "/usr/nekoware/bin/youtube-dl/youtube_dl/extractor/generic.py", line 2236, in _real_extract
File "/usr/nekoware/bin/youtube-dl/youtube_dl/extractor/common.py", line 818, in _search_json_ld
File "/usr/nekoware/bin/youtube-dl/youtube_dl/extractor/common.py", line 826, in _json_ld
AttributeError: 'list' object has no attribute 'get'

[yan12125]

An example of multiple node objects in JSON-LD: https://www.w3.org/TR/json-ld/#named-graphs Such objects should be handled.