code: def extend_validators(raw_validators, override_validators):
      
  
      if not raw_validators:
          return override_validators
  
      elif not override_validators:
          return raw_validators
  
      else:
          def_validators_mapping = _convert_validators_to_mapping(raw_validators)
          ref_validators_mapping = _convert_validators_to_mapping(override_validators)
  
          def_validators_mapping.update(ref_validators_mapping)
          return list(def_validators_mapping.values())
docs: extend raw_validators with override_validators.
          override_validators will merge and override raw_validators.
  
      Args:
          raw_validators (dict):
          override_validators (dict):
  
      Returns:
          list: extended validators
  
      Examples:
          >>> raw_validators = [{'eq': ['v1', 200]}, {"check": "s2", "expect": 16, "comparator": "len_eq"}]
          >>> override_validators = [{"check": "v1", "expect": 201}, {'len_eq': ['s3', 12]}]
          >>> extend_validators(raw_validators, override_validators)
              [
                  {"check": "v1", "expect": 201, "comparator": "eq"},
                  {"check": "s2", "expect": 16, "comparator": "len_eq"},
                  {"check": "s3", "expect": 12, "comparator": "len_eq"}
              ]