proc cmpCountTablePair[A](a, b: tuple[key: A, val: int]): int =
  ## compare proc for a data item of a CountTable
  if a.val > b.val: return -1
  if a.val < b.val: return 1
  return cmp(a.key, b.key)

proc sort*[A](t: var CountTable[A]) =
  ## sorts the count table so that the entry with the highest counter comes
  ## first. This is destructive! You must not modify `t` afterwards!
  ## You can use the iterators `pairs`,  `keys`, and `values` to iterate over
  ## `t` in the sorted order.
  t.data.sort(cmp=cmpCountTablePair)