public static IEnumerable <string> GetAllEthereumSubChains(this BTCPayNetworkProvider networkProvider, BTCPayNetworkProvider unfiltered) { var ethBased = networkProvider.GetAll().OfType <EthereumBTCPayNetwork>(); var chainId = ethBased.Select(network => network.ChainId).Distinct(); return(unfiltered.GetAll().OfType <EthereumBTCPayNetwork>() .Where(network => chainId.Contains(network.ChainId)) .Select(network => network.CryptoCode.ToUpperInvariant())); }