code: def increase_verbosity():
      
      defined_levels = sorted(set(find_defined_levels().values()))
      current_index = defined_levels.index(get_level())
      selected_index = max(0, current_index - 1)
      set_level(defined_levels[selected_index])
docs: Increase the verbosity of the root handler by one defined level.
  
      Understands custom logging levels like defined by my ``verboselogs``
      module.