code: def sigmoid_sign(ary, thresh):
      def sigmoid(x):
          return 1 / (1 + np.exp(-x * np.e)) - 0.5
  
      return sigmoid(ary / thresh) * thresh
  
imports: from __future__ import annotations
  import datetime
  import threading
  import time
  import alpaca_trade_api
  import gym
  import numpy
  import pandas
  import torch
  from finrl.meta.data_processors.processor_alpaca import AlpacaProcessor
  from finrl.meta.paper_trading.common import AgentPPO
label_desc: Use image node_id 8 for calling the PaperTradingAlpaca obj's underlying member method code with example usage: obj.sigmoid_sign(ary, thresh) and returns: unknown, unknown