public virtual ICollection <K3> ThirdKeySet()
{
ICollection <K3> keys = Generics.NewHashSet();
foreach (K1 k1 in map.Keys)
{
ThreeDimensionalMap <K2, K3, K4, V> m3 = map[k1];
foreach (K2 k2 in m3.FirstKeySet())
{
Sharpen.Collections.AddAll(keys, m3.Get(k2).FirstKeySet());
}
}
return(keys);
}
public virtual ICollection <K4> FourthKeySet()
{
ICollection <K4> keys = Generics.NewHashSet();
foreach (K1 k1 in map.Keys)
{
ThreeDimensionalMap <K2, K3, K4, V> m3 = map[k1];
foreach (K2 k2 in m3.FirstKeySet())
{
TwoDimensionalMap <K3, K4, V> m2 = m3.Get(k2);
foreach (K3 k3 in m2.FirstKeySet())
{
Sharpen.Collections.AddAll(keys, m2.Get(k3).Keys);
}
}
}
return(keys);
}