class_docstr: Tests whether short opts with multiple letters parse correctly.
  
  Known tricky in python 3.8.
class_docstr_tok: ["Tests","whether","short","opts","with","multiple","letters","parse","correctly",".","Known","tricky","in","python","3.8","."]
code: def setup_args(cls):
      parser = ParlaiParser(True, True, description="Short opt test")
      parser.add_argument("-m", "--model")
      parser.add_argument("-mxx", "--my-other-option")
      return parser
  
imports: import sys
  import unittest
  from unittest.mock import patch
  from parlai.core.params import ParlaiParser
  import parlai.core.script
  import parlai.utils.testing
label_desc: Use image node_id 1 for calling the _TestShortOptScript obj's underlying member method code with example usage: obj.setup_args(cls) and returns: parser