Downloading From Discovery's MotorTrend Using Cookies Throws Error Related To Cookies

[phoenixnodes]

Checklist

• [x ] I'm reporting a broken site support issue
• [x ] I've verified that I'm running youtube-dl version 2020.03.24
• [x ] I've checked that all provided URLs are alive and playable in a browser
• [x ] I've checked that all URLs and arguments with special characters are properly quoted or escaped
• [x ] I've searched the bugtracker for similar bug reports including closed ones
• [x ] I've read bugs section in FAQ

Verbose log

[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: [u'--cookies=cookies.txt', u'https://watch.motortrend.com/tv-shows/bitchin-rides/full-episodes/daves-new-toy', u'-v']
[debug] Encodings: locale cp1252, fs mbcs, out cp437, pref cp1252
[debug] youtube-dl version 2020.03.24
[debug] Python version 2.7.17 (CPython) - Windows-10-10.0.18362
[debug] exe versions: ffmpeg N-93719-g19af948e53, ffprobe N-93719-g19af948e53, rtmpdump 2.4
[debug] Proxy map: {}
Traceback (most recent call last):
  File "c:\python27\lib\runpy.py", line 174, in _run_module_as_main
    "__main__", fname, loader, pkg_name)
  File "c:\python27\lib\runpy.py", line 72, in _run_code
    exec code in run_globals
  File "C:\Python27\Scripts\youtube-dl.exe\__main__.py", line 7, in <module>
  File "c:\python27\lib\site-packages\youtube_dl\__init__.py", line 474, in main
    _real_main(argv)
  File "c:\python27\lib\site-packages\youtube_dl\__init__.py", line 464, in _real_main
    retcode = ydl.download(all_urls)
  File "c:\python27\lib\site-packages\youtube_dl\YoutubeDL.py", line 2019, in download
    url, force_generic_extractor=self.params.get('force_generic_extractor', False))
  File "c:\python27\lib\site-packages\youtube_dl\YoutubeDL.py", line 797, in extract_info
    ie_result = ie.extract(url)
  File "c:\python27\lib\site-packages\youtube_dl\extractor\common.py", line 530, in extract
    ie_result = self._real_extract(url)
  File "c:\python27\lib\site-packages\youtube_dl\extractor\discovery.py", line 68, in _real_extract
    cookies = self._get_cookies(url)
  File "c:\python27\lib\site-packages\youtube_dl\extractor\common.py", line 2831, in _get_cookies
    return compat_cookies.SimpleCookie(req.get_header('Cookie'))
  File "c:\python27\lib\Cookie.py", line 583, in __init__
    if input: self.load(input)
  File "c:\python27\lib\Cookie.py", line 643, in load
    for k, v in rawdata.items():
AttributeError: 'unicode' object has no attribute 'items'

Description

Using youtube-dl to download a video from Discovery's MotorTrend website, the video is available and playable but the issue seems to be with cookies from what the logs say.