code: def netreturn(f, c, o=1):
      r"""Calculate the net return, or Return On Invesment (ROI)
  
      Parameters
      ----------
      f : pandas.DataFrame
          Dataframe containing the column ``c``.
      c : str
          Name of the column in the dataframe ``f``.
      o : int, optional
          Offset value for shifting the series.
  
      Returns
      -------
      new_column : pandas.Series (float)
          The array containing the new feature.
  
      References
      ----------
      *ROI measures the amount of return on an investment relative to the
      original cost. To calculate ROI, the benefit (or return) of an
      investment is divided by the cost of the investment, and the result
      is expressed as a percentage or a ratio* [IP_ROI]_.
  
      .. [IP_ROI] http://www.investopedia.com/terms/r/returnoninvestment.asp
  
      """
      new_column = 100 * pchange1(f, c, o)
      return new_column
  
imports: from alphapy.calendrical import biz_day_month
  from alphapy.calendrical import biz_day_week
  from alphapy.globals import NULLTEXT
  from alphapy.globals import BSEP, PSEP, USEP
  from alphapy.variables import vexec
  import itertools
  import logging
  import math
  import numpy
  import pandas
label_desc: Use image node_id 33 for calling a global function with example usage: netreturn(f, c, o) and returns: new_column