code: def check_log_stream_exists(awsclient, log_group_name, log_stream_name):
      
      lg = describe_log_group(awsclient, log_group_name)
      if lg and lg['logGroupName'] == log_group_name:
          stream = describe_log_stream(awsclient, log_group_name, log_stream_name)
          if stream and stream['logStreamName'] == log_stream_name:
              return True
      return False
docs: Check
  
      :param log_group_name: log group name
      :param log_stream_name: log stream name
      :return: True / False