code: def _cumulative_returns_less_costs(returns, costs):
      """
      Compute cumulative returns, less costs.
      """
      if costs is None:
          return ep.cum_returns(returns)
      return ep.cum_returns(returns - costs)
  
file_path: pyfolio/pyfolio/perf_attrib.py
imports: from __future__ import division
  import warnings
  from collections import OrderedDict
  import empyrical
  import pandas
  import matplotlib.pyplot
  from .pos import get_percent_alloc
  from .txn import get_turnover
  from .utils import print_table, configure_legend
label_desc: Use image node_id 11 for calling a global function with example usage: _cumulative_returns_less_costs(returns, costs) and returns: ep, ep