getFee method
Implementation
Future<PolyAmount> getFee() async {
final network = await getNetwork();
if (network == toplnet) {
return PolyAmount.fromUnitAndValue(PolyUnit.nanopoly, toplnetFee);
} else if (network == valhalla) {
return PolyAmount.fromUnitAndValue(PolyUnit.nanopoly, valhallaFee);
} else {
return PolyAmount.zero();
}
}