code: def boolWithSubParams(parameters, name):
      
      param = parameters.find(".//BoolWithSubParams[@Name='{name}']".format(name=name))
      str_value = param.find('Value').text
      if str_value not in {'true', 'false'}:
          raise ValueError('BoolParamWithSubParams Value has to be either "true" or "false", was {}'.format(str_value))
      value = str_value == 'true'
      choice = 'SubParamsTrue' if value else 'SubParamsFalse'
      return value, param.find('{}/Parameters'.format(choice))
docs: single choice with sub parameters value and chosen subparameters. Returns -1 and None if no value was chosen.
      :param parameters: the parameters tree.
      :param name: the name of the parameter.