code: def clean_cell(self, cell, cell_type):
          
          try:
              # Get rid of non-ASCII characters
              cell = cell.encode('ascii', 'ignore').decode()
              if cell_type == 'D':
                  cell = datetime.strptime(cell, '%Y%m%d')
              elif cell_type == 'I':
                  cell = int(cell)
              elif cell_type == 'N':
                  cell = Decimal(cell)
              else:
                  cell = cell.upper()
  
                  if len(cell) > 50:
                      cell = cell[0:50]
  
                  if not cell or cell in NULL_TERMS:
                      cell = None
  
          except:
              cell = None
  
          return cell
docs: Uses the type of field (from the mapping) to
          determine how to clean and format the cell.