code: def validated_value(self, raw_value):
          
          value = self.value(raw_value)
          try:
              for validator in self.validators:
                  validator(value)
          except:
              raise
          else:
              return value
docs: Return parsed parameter value and run validation handlers.
  
          Error message included in exception will be included in http error
          response
  
          Args:
              value: raw parameter value to parse validate
  
          Returns:
              None
  
          Note:
              Concept of validation for params is understood here as a process
              of checking if data of valid type (successfully parsed/processed by
              ``.value()`` handler) does meet some other constraints
              (lenght, bounds, uniqueness, etc.). It will internally call its
              ``value()`` handler.