* Note how dummy entry re-use benefits use cases with interspersed deletes   and adds.
* Note how dummy entry re-use benefits use cases with interspersed deletes
  and adds.

* Note that dictionary iteration is negatively impacted by additional
  sparseness.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator