code: def truehigh(f):
      r"""Calculate the *True High* value.
  
      Parameters
      ----------
      f : pandas.DataFrame
          Dataframe with columns ``high`` and ``low``.
  
      Returns
      -------
      new_column : pandas.Series (float)
          The array containing the new feature.
  
      References
      ----------
      *Today's high, or the previous close, whichever is higher* [TS_TR]_.
  
      .. [TS_TR] http://help.tradestation.com/09_01/tradestationhelp/charting_definitions/true_range.htm
  
      """
      c1 = "low[1]"
      vexec(f, c1)
      c2 = "high"
      new_column = f.apply(c2max, axis=1, args=[c1, 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 45 for calling a global function with example usage: truehigh(f) and returns: new_column