This is an implementation of an ordered dictionary with Key Insertion Order (KIO: updates of values do not affect the position of the key), Key Value Insertion Order (KVIO, an existing key’s position is removed and put at the back). The standard library module OrderedDict, implemented later, implements a subset of ordereddict functionality.

Sorted dictionaries are also provided. Currently only with Key Sorted Order (KSO, no sorting function can be specified, but you can specify a transform to apply on the key before comparison (e.g. string.lower)).