code: public MerkleTreeConfig setDepth(int depth) {
          if (depth < MIN_DEPTH || depth > MAX_DEPTH) {
              throw new IllegalArgumentException("Merkle tree depth " + depth + " is outside of the allowed range "
                      + MIN_DEPTH + "-" + MAX_DEPTH + ". ");
          }
          this.depth = depth;
          return this;
      }
docs: Sets the depth of the merkle tree. The depth must be between
  {@value MAX_DEPTH} and {@value MIN_DEPTH} (exclusive).
  
  @param depth the depth of the merkle tree
  @return the updated config
  @throws ConfigurationException if the {@code depth} is greater than
  {@value MAX_DEPTH} or less than {@value MIN_DEPTH}