docs: def median_fill(adf):
          """ Looks at each row, and chooses the median. Honours
          the Trump override/failsafe logic. """
          ordpt = adf.values[0]
          if not pd.isnull(ordpt):
              return ordpt
  
          fdmn = adf.iloc[1:-1].median()
          if not pd.isnull(fdmn):
              return fdmn
  
          flspt = adf.values[-1]
          if not pd.isnull(flspt):
              return flspt
  
          return nan