code: def parse_row(self):
          
          fields = self.mapping
          for i, cell in enumerate(self.row[0:len(fields)]):
              field_name, field_type = fields[str(i)]
              parsed_cell = self.clean_cell(cell, field_type)
              self.parsed_row[field_name] = parsed_cell
docs: Parses a row, cell-by-cell, returning a dict of field names
          to the cleaned field values.