parameters: (self)
docstring: override this function for a new command
          :return:
docstring_summary: override this function for a new command
          :return:
docstring_tokens: override this function for a new command : return :
function: def exec(self):
          """
          override this function for a new command
          :return:
          """
          raise NotImplementedError()
function_tokens: def exec ( self ) : raise NotImplementedError ( )