Traceback (most recent call last):

 "./test_cumprod.py", line 13, in <module>
foo.cumprod()

 "/Users/pwolfram/anaconda/lib/python2.7/site-packages/xarray/core/common.py", line 16, in wrapped_func
skipna=skipna, allow_lazy=True, **kwargs)

 "/Users/pwolfram/anaconda/lib/python2.7/site-packages/xarray/core/dataarray.py", line 991, in reduce
var = self.variable.reduce(func, dim, axis, keep_attrs, **kwargs)

 "/Users/pwolfram/anaconda/lib/python2.7/site-packages/xarray/core/variable.py", line 880, in reduce
return Variable(dims, data, attrs=attrs)

 "/Users/pwolfram/anaconda/lib/python2.7/site-packages/xarray/core/variable.py", line 213, in __init__
self._dims = self._parse_dimensions(dims)

 "/Users/pwolfram/anaconda/lib/python2.7/site-packages/xarray/core/variable.py", line 321, in _parse_dimensions
% (dims, self.ndim))ValueError: dimensions () must have the same length as the number of data dimensions, ndim=1
ERROR: Signature extraction failed: Traceback (most recent call last):

 "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 479, in _decrypt_signature
video_id, player_url, s

 "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 383, in _extract_signature_function
res = self._parse_sig_js(code)

 "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 454, in _parse_sig_js
u'Initial JS player signature function name')

 "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/common.py", line 391, in _search_regex
raise RegexNotFoundError(u'Unable to extract %s' % _name)RegexNotFoundError: Unable to extract Initial JS player signature function name; please report this issue on https://yt-dl.org/bug . Be sure to call youtube-dl with the --verbose flag and include its complete output. Make sure you are using the latest version; type
youtube-dl -U
to update.