Design considerations and tradeoffs

When working with containers and collections, we have a multistep design strategy:

1. Consider the built-in versions of sequence, mapping, and set.
2. Consider the library extensions in the collection module, as well as extras such as heapq, bisect, and array.
3. Consider a composition of existing class definitions. In many cases, a list of tuple objects or a dict of lists provides the needed features.
4. Consider extending one of the earlier mentioned classes to provide additional methods or attributes.
5. Consider wrapping an existing structure as another way to provide additional methods or attributes.
6. Finally, consider a novel data structure. Generally, there is a lot of careful analysis available. Start with Wikipedia articles such as this one: http://en.wikipedia.org/wiki/List_of_data_structures.

Once the design alternatives have been identified, there...