code: def _expand_error_codes(code_parts):
          
          codes = set(ErrorRegistry.get_error_codes())
          expanded_codes = set()
  
          try:
              for part in code_parts:
                  # Dealing with split-lined configurations; The part might begin
                  # with a whitespace due to the newline character.
                  part = part.strip()
                  if not part:
                      continue
  
                  codes_to_add = {code for code in codes
                                  if code.startswith(part)}
                  if not codes_to_add:
                      log.warning(
                          'Error code passed is not a prefix of any '
                          'known errors: %s', part)
                  expanded_codes.update(codes_to_add)
          except TypeError as e:
              raise IllegalConfiguration(e)
  
          return expanded_codes
docs: Return an expanded set of error codes to ignore.