docs: def customwarn(message, category, filename, lineno, *args, **kwargs):
      """Use the psyplot.warning logger for categories being out of
      PsyPlotWarning and PsyPlotCritical and the default warnings.showwarning
      function for all the others."""
      if category is PsyPlotWarning:
          logger.warning(warnings.formatwarning(
              "\n%s" % message, category, filename, lineno))
      elif category is PsyPlotCritical:
          logger.critical(warnings.formatwarning(
              "\n%s" % message, category, filename, lineno),
              exc_info=True)
      else:
          old_showwarning(message, category, filename, lineno, *args, **kwargs)