wrong condition processing for entities

[buchslava]

dataset is SG
query is

{
        from: 'entities',
        select: {
          key: ['geo'],
          value: ['name', 'world_4region', 'latitude', 'longitude']
        },
        where: {'is--country': true}
      }

current result an empty array
expected result: counties should be selected

ps: when I'm trying where: {} - it selects all of the entities