The peak.util.extremes module provides a production-quality implementation of
the Min and Max objects from PEP 326. While PEP 326 was rejected for inclusion
in the language or standard library, the objects described in it are useful in
a variety of applications. In PEAK, they have been used to implement generic
functions (in RuleDispatch and PEAK-Rules), as well as to handle scheduling and
time operations in the Trellis. Because this has led to each project copying
the same code, we've now split the module out so it can be used independently.