def __init__(self, master=None, **kw):
        Widget.__init__(self, master, "ttk::button", kw)
Return the string hash of the review branch or None.
dataset/ETHPy150Open francelabs/datafari/windows/python/Lib/lib-tk/ttk.py/Button.__init__--crossover with--dataset/ETHPy150Open bloomberg/phabricator-tools/py/abd/abdt_branch.py/Branch.review_branch_hash