def each
      index = 0
      while index < i_keys.get_length
        key = i_keys.get(index)
        value = i_values.get(index)
        yield key , value
        index = index + 1
      end
      self
    end
def each
      index = 0
      while index < i_keys.get_length
        key = i_keys.get(index)
        value = i_values.get(index)
        yield key , value
        index = index + 1
      end
      self
    end
yield to each key value pair