code: def normalize(returns, starting_value=1):
      """
      Normalizes a returns timeseries based on the first value.
  
      Parameters
      ----------
      returns : pd.Series
          Daily returns of the strategy, noncumulative.
           - See full explanation in tears.create_full_tear_sheet.
      starting_value : float, optional
         The starting returns (default 1).
  
      Returns
      -------
      pd.Series
          Normalized returns.
      """
  
      return starting_value * (returns / returns.iloc[0])
  
imports: from __future__ import division
  from collections import OrderedDict
  from functools import partial
  import empyrical
  import numpy
  import pandas
  import scipy
  import scipy.stats
  from sklearn import linear_model
  from .deprecate import deprecated
  from .interesting_periods import PERIODS
  from .txn import get_turnover
  from .utils import APPROX_BDAYS_PER_MONTH, APPROX_BDAYS_PER_YEAR
  from .utils import DAILY
label_desc: Use image node_id 16 for calling a global function with example usage: normalize(returns, starting_value) and returns: unknown