`log` package now support string formatting method

Following RFC-265 it is now possible to use Python string format() method syntax in log messages. For each of the standard logging methods, log, warn, info, debug etc, there are now f variants that support string formatting: logf, warnf, infof, debugf etc.

For example

log.warnf(“Value: {}”, value)
log.infof(“Swap: {1} <-> {0} {places}”, 2, 1, places=“Tucson”)

All the normal str.format() syntax should work.