def WriteCollapsedDependencies(self, name, targets, order_only=None):

    assert targets == filter(None, targets), targets
    if len(targets) == 0:
      assert not order_only
      return None
    if len(targets) > 1 or order_only:
      stamp = self.GypPathToUniqueOutput(name + '.stamp')
      targets = self.ninja.build(stamp, 'stamp', targets, order_only=order_only)
      self.ninja.newline()
    return targets[0]
Concat a map. You can also optionally slice the operand map
dataset/ETHPy150Open adblockplus/gyp/pylib/gyp/generator/ninja.py/NinjaWriter.WriteCollapsedDependencies--crossover with--dataset/ETHPy150Open chriso/gauged/gauged/structures/sparse_map.py/SparseMap.concat