code: def init(parser = None):
      
  
      global p,subparsers
      if parser is None:
          p = argparse.ArgumentParser()
      else:
          p = parser
  
      arg = p.add_argument
  
      subparsers = p.add_subparsers()
docs: module needs to be initialized by 'init'.
  
      Can be called with parser to use a pre-built parser, otherwise
      a simple default parser is created