[$] Explicit lazy imports for Python

Importing modules in Python is ubiquitous; most Python programs start
with at least a few import statements. But the performance impact
of those imports can be large—and may be entirely wasted effort if the
symbols imported end up being unused. There are multiple ways to lazily
import modules, including one in the standard library, but none of them are
part of the Python language itself. That
may soon change, if the recently proposed
PEP 810 ('Explicit lazy
imports') is approved.