old_contents: def isblank(value):
      return (
              value is not False
              and value != 0
              and value != float(0)
              and not bool(value)
      )
  
  
  def concatenate(delimiter=''):
      def _concatenate(row):
          return delimiter.join(row)
  
      return _concatenate
  
  
  def nvl(default=''):
      def _nvl(row):
          return next((v for v in row if not isblank(v)), default)
  
      return _nvl
  
new_contents: import pandas as pd
  
  def isblank(value):
      return (
          value is not False
          and value != 0
          and value != float(0)
          and (value is None or pd.isnull(value) or not value)
      )
  
  def concatenate(delimiter=''):
      def _concatenate(row):
          return delimiter.join(row)
      return _concatenate
  
  def nvl(default=''):
      def _nvl(row):
          return next((v for v in row if not isblank(v)), default)
      return _nvl
  
subject: Revert "DE-1903 - fix isblank() error"