code: def gtval(f, c1, c2):
      r"""Determine whether or not the first column of a dataframe
      is greater than the second.
  
      Parameters
      ----------
      f : pandas.DataFrame
          Dataframe containing the two columns ``c1`` and ``c2``.
      c1 : str
          Name of the first column in the dataframe ``f``.
      c2 : str
          Name of the second column in the dataframe ``f``.
  
      Returns
      -------
      new_column : pandas.Series (bool)
          The array containing the new feature.
  
      """
      new_column = f[c1] > f[c2]
      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 22 for calling a global function with example usage: gtval(f, c1, c2) and returns: new_column