def get(key)
      index = index_for(key)
      entry = @entries[index]
      if entry && entry[0].eql?(key)
        entry
      else
        child = @children[index]
        child.get(key) if child
      end
    end
def get(key)
      index = index_for(key)
      entry = @entries[index]
      if entry && entry[0].eql?(key)
        entry
      else
        child = @children[index]
        child.get(key) if child
      end
    end
Retrieves the entry corresponding to the given key. If not found, returns <tt>nil</tt>.