code: def get_turnover_rate():
      # in backtest
      pass
  
imports: from __future__ import division
  from __future__ import print_function
  import numpy
  import pandas
  from scipy.stats import spearmanr, pearsonr
  from ..data import D
  from collections import OrderedDict
label_desc: Use image node_id 9 for calling a global function with example usage: get_turnover_rate() without return types