code: def validate(self, path, schema, value, results):
          
          name = path if path != None else "value"
          found = False
  
          for this_value in self._values:
              if this_value != None and this_value == value:
                  found = True
                  break
  
          if not found:
              results.append(
                  ValidationResult(
                      path,
                      ValidationResultType.Error,
                      "VALUE_NOT_INCLUDED",
                      name + " must be one of " + str(self._values),
                      self._values,
                      value
                  )
              )
docs: Validates a given value against this rule.
  
          :param path: a dot notation path to the value.
  
          :param schema: a schema this rule is called from
  
          :param value: a value to be validated.
  
          :param results: a list with validation results to add new results.