question: public DeterministicKey ( ImmutableList < ChildNumber > childNumberPath , byte [ ] chainCode , BigInteger priv , @ Nullable DeterministicKey parent ) { super ( priv , compressPoint ( ECKey . publicPointFromPrivate ( priv ) ) ) ; checkArgument ( chainCode . length == 32 ) ; this . parent = parent ; this . childNumberPath = checkNotNull ( childNumberPath ) ; this . chainCode = Arrays . copyOf ( chainCode , chainCode . length ) ; this . depth = parent == null ? 0 : parent . depth + 1 ; this . parentFingerprint = ( parent != null ) ? parent . getFingerprint ( ) : 0 ; }
target:  Constructs a key from its components. This is not normally something you should use. 