pylint error resolution

ml-agents-envs/mlagents_envs/environment.py

                 launch_string = candidates[0]
         return launch_string
 
-
-        cwd = os.getcwd()
         file_name = (
             file_name.strip()
             .replace(".app", "")

ml-agents/mlagents/trainers/learn.py

 import numpy as np
 import json
 
-from sys import platform
 from typing import Callable, Optional, List, NamedTuple, Dict
 
 import mlagents.trainers