private func processExhibitions() async throws { var processedExhibitions: [ProcessedExhibition?] = Array(repeating: nil, count: exhibitions.count) try await withThrowingTaskGroup(of: (Int, ProcessedExhibition?).self, body: { [weak self] taskGroup in guard let self else { return } for (idx, exhibition) in exhibitions.enumerated() { if let posterUrl = exhibition.pos..