v1.4.0

What's Changed

• The deprecated module-level minpq and maxpq have been removed in favor of same-named classmethods introduced in v1.3.0 (#24)
• Introduce a distinct Empty exception for operations that attempt to remove items from an empty pqdict, instead of raising a KeyError. (Note that Empty is derived from KeyError for subclass compatibility with Mapping.popitem and Mapping.clear.) (#24)
• Make internal heap nodes immutable and fast copy as originally proposed by @palkeo in #14

Maintenance

• Factored out indexed heap operations to reduce redundancy
• Better docstrings and type annotations

Full Changelog: v1.3.0...v1.4.0