is None,
    which gives each value a weight of 1.0

Returns
-------
braycurtis : double
    The Bray-Curtis distance between 1-D arrays `u` and `v`.

Examples
--------
>>> from scipy.spatial import distance
>>> distance.braycurtis([1, 0, 0], [0, 1, 0])
1.0
>>> distance.braycurtis([1, 1, 0], [0, 1, 0])
0.33333333333333331

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