template partitionIt*[T](s: openArray[T], pred: untyped): tuple[t: seq[T], f: seq[T]] =
  ## Returns a tuple that contains two sequences.
  ## The first sequence contains the items that fulfill the predicate.
  ## The second sequence contains the items that do not fulfill the predicate.
  runnableExamples:
    import sequtils
    let
      temperatures = @[-272.15, -2.0, 24.5, 44.31, 99.9, -113.44]
      acceptable = filterIt(temperatures, it < 50 and it > -10)
      notAcceptable = filterIt(temperatures, it > 50 or it < -10)
      partitions = partitionIt(temperatures, it < 50 and it > -10)
    assert acceptable == @[-2.0, 24.5, 44.31]
    assert notAcceptable == @[-272.15, 99.9, -113.44]
    assert partitions[0] == acceptable
    assert partitions[1] == notAcceptable

  var
    t = newSeq[T]()
    f = newSeq[T]()
  for it {.inject.} in items(s):
    if pred:
      t &= it
    else:
      f &= it
  (t: t, f: f)