code: def parse_methods(csv_file, errors_dict):
      
      with csv_file.open(newline='') as f:
          f = csv.reader(f)
          next(f, None)  # header
          for line, (method, usability, errors) in enumerate(f, start=2):
              try:
                  errors = [errors_dict[x] for x in errors.split()]
              except KeyError:
                  raise ValueError('Method {} references unknown errors {}'
                                   .format(method, errors)) from None
  
              yield MethodInfo(method, usability, errors)
docs: Parses the input CSV file with columns (method, usability, errors)
      and yields `MethodInfo` instances as a result.