def _dfs(self, visited):
        if self not in visited:
            visited.add(self)
            for successor in self._children + self._followOns:
                successor._dfs(visited)
Verifies that a build of the specified Xcode target is up to date.
dataset/ETHPy150Open BD2KGenomics/toil/src/toil/job.py/Job._dfs--crossover with--dataset/ETHPy150Open adblockplus/gyp/test/lib/TestGyp.py/TestGypXcode.up_to_date