code: def c2min(f, c1, c2):
      r"""Take the minimum value between two columns in a dataframe.
  
      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
      -------
      min_val : float
          The minimum value of the two columns.
  
      """
      min_val = min(f[c1], f[c2])
      return min_val
  
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 5 for calling a global function with example usage: c2min(f, c1, c2) and returns: min_val