code: def transform_parameter_value(parameter_name, value, parameter_config):
    if isinstance(value, list):
      return [transform_parameter_value('%s[%d]' % (parameter_name, index),
                                        element, parameter_config)
              for index, element in enumerate(value)]
    entry = _get_parameter_conversion_entry(parameter_config)
    if entry:
      validation_func, conversion_func, type_name = entry
      if validation_func:
        validation_func(parameter_name, value, parameter_config)
      if conversion_func:
        try:
          return conversion_func(value)
        except ValueError:
          raise errors.BasicTypeParameterError(parameter_name, value, type_name)
    return value