AvlSortedMultiSet[T] = object
  root*: AvlTreeNode[T]

AVLSortedSet[T] = object
  root*: AvlTreeNode[T]

AvlTreeNode[K] = ptr AvlTreeNodeObj[K]

AvlTreeNodeObj[K] = object
  l*, r*, p*: AvlTreeNode[K]
  h*, len*: int
  key*: K

CPLIB_COLLECTIONS_AVLSET = 1

proc `$`[T](self: AVLSets[T]): string

proc `[]`[T](self: AVLSets[T]; idx: BackwardsIndex): T

proc `[]`[T](self: AVLSets[T]; idx: int): T

proc contains[T](self: AVLSets[T]; x: T): bool

proc count[T](self: AVLSets[T]; x: T): int

proc excl[T](self: var AVLSets[T]; x: T): bool {.discardable.}

proc ge[T](self: AVLSets[T]; x: T): Option[T]

proc gt[T](self: AVLSets[T]; x: T): Option[T]

proc incl[T](self: var AvlSortedMultiSet[T]; x: T)

proc incl[T](self: var AVLSortedSet[T]; x: T): bool {.discardable.}

proc index[T](self: AVLSets[T]; x: T): int

proc index_right[T](self: AVLSets[T]; x: T): int

proc initAvlSortedMultiSet[T](v: openArray[T] = []): AvlSortedMultiSet[T]

proc initAvlSortedSet[T](v: openArray[T] = []): AVLSortedSet[T]

proc le[T](self: AVLSets[T]; x: T): Option[T]

proc len[T](self: AVLSets[T]): int

proc lowerBound[T](self: AVLSets[T]; x: T): int

proc lt[T](self: AVLSets[T]; x: T): Option[T]

proc pop[T](self: var AVLSets[T]; idx: int = -1): T

proc upperBound[T](self: AVLSets[T]; x: T): int

iterator items[T](self: AVLSets[T]): T