[$] Reducing Python's startup time

The startup time for the Python interpreter has been discussed by the coredevelopers and others numerous times over the years; optimization effortsare made periodically as well.Startup time can dominate the execution time of command-line programswritten in Python,especially if they import a lot of other modules. Python startup time isworse than some other scripting languages and more recent versions of thelanguage are taking more than twice as long to start up when compared toearlier versions (e.g. 3.7 versus 2.7).The most recent iteration of the startup timediscussion has played out in the python-dev and python-ideas mailing listssince mid-July. This time, the focus has been on the collections.namedtuple()data structure that is used in multiple places throughout the standardlibrary and in other Python modules, but the discussion has been morewide-ranging than simply that.