code: def keys_by_creation(group):
      
      from h5py import h5
      out = []
      try:
          group._id.links.iterate(
              out.append, idx_type=h5.INDEX_CRT_ORDER, order=h5.ITER_INC)
      except (AttributeError, RuntimeError):
          # pre 2.2 shim
          def f(name):
              if name.find(b'/', 1) == -1:
                  out.append(name)
          group._id.links.visit(
              f, idx_type=h5.INDEX_CRT_ORDER, order=h5.ITER_INC)
      return map(group._d, out)
docs: Returns a sequence of links in group in order of creation.
  
      Raises an error if the group was not set to track creation order.