BEVSTD: Empty result set for certain regions

[sjockers]

See CorrelAid/datenguide-python#75:

The following query does not yield any data, even though there should be data available for that region:

query {
  region(id: "08226098") {
    name
    BEVSTD(year: 2018, ALTX20: ALT030B35) {
      value
      year
      ALTX20
      source {
        name
        title_de
      }
    }
  }
}

The same query works for the surrounding Landkreis though:

query {
  region(id: "08226") {
    name
    BEVSTD(year: 2018, ALTX20: ALT030B35) {
      value
      year
      ALTX20
      source {
        name
        title_de
      }
    }
  }
}

[dpprdan]

See also datenguide/genesapi-tabular#19