code: def get_command_instance(name, parent=None, checkexists=True):
      
      cname = "%sCommand" % name.lower().capitalize()
      gl = globals()
      condition = (
          cname not in gl or
          (checkexists and gl[cname].extension and
           gl[cname].extension not in RequireCommand.loaded_extensions)
      )
      if condition:
          raise UnknownCommand(name)
      return gl[cname](parent)
docs: Try to guess and create the appropriate command instance
  
      Given a command name (encountered by the parser), construct the
      associated class name and, if known, return a new instance.
  
      If the command is not known or has not been loaded using require,
      an UnknownCommand exception is raised.
  
      :param name: the command's name
      :param parent: the eventual parent command
      :return: a new class instance