public static HMap <A, HMap <B, HMap <C, HMap <D, T> > > > Remove <A, B, C, D, T>(this HMap <A, HMap <B, HMap <C, HMap <D, T> > > > self, A aKey, B bKey, C cKey, D dKey)
{
var res = self.Find(aKey, bKey, cKey);
if (res.IsSome && res.CountT() > 1)
{
return(self.SetItemT(aKey, bKey, cKey, res.Lift().Remove(dKey)));
}
else
{
if (res.IsSome)
{
if (res.MapT(d => d.ContainsKey(dKey)).Lift())
{
return(Remove(self, aKey, bKey, cKey));
}
else
{
return(self);
}
}
else
{
return(Remove(self, aKey, bKey, cKey));
}
}
}