code: def init(self):
      self.sma1 = self.I(SMA, self.data.Close, self.n1)
      self.sma2 = self.I(SMA, self.data.Close, self.n2)
      self.sma_enter = self.I(SMA, self.data.Close, self.n_enter)
      self.sma_exit = self.I(SMA, self.data.Close, self.n_exit)
  
file_path: backtesting.py/doc/examples/Parameter Heatmap & Optimization.py
imports: from backtesting.test import SMA
  from backtesting import Strategy
  from backtesting.lib import crossover
  from backtesting import Backtest
  from backtesting.test import GOOG
  import seaborn
  from backtesting.lib import plot_heatmaps
  from skopt.plots import plot_objective
  from skopt.plots import plot_evaluations
label_desc: Use image node_id 1 for calling the Sma4Cross obj's underlying member method code with example usage: obj.init() without return types