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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _all_combos(self):
 """ RETURN AN ITERATOR OF ALL COORDINATES """

        combos = _product(self.dims)
        if not combos:
            return

        calc = [(coalesce(_product(self.dims[i+1:]), 1), mm) for i, mm in enumerate(self.dims)]

        for c in xrange(combos):
            yield tuple(int(c / dd) % mm for dd, mm in calc)