code: def func(data_row, wait):
      ''' A sample function
      It takes 'wait' seconds to calculate the sum of each row
      '''
      time.sleep(wait)
      data_row['sum'] = data_row['col_1'] + data_row['col_2']
      return data_rof func(data_row, wait):
      ''' A sample function
      It takes 'wait' seconds to calculate the sum of each row
      '''
      time.sleep(wait)
      data_row['sum'] = data_row['col_1'] + data_row['col_2']
      return data_row
docs: A sample function
      It takes 'wait' seconds to calculate the sum of each row