asBool function
Implementation
bool asBool(dynamic v, [bool def = false]) {
if (v == null) return def;
if (v is bool) return v;
if (v is num) return v != 0;
final s = v.toString().toLowerCase();
if (s == 'true' || s == 'y' || s == '1') return true;
if (s == 'false' || s == 'n' || s == '0') return false;
return def;
}