def [](input)
      key = __convert_key(input)
      return @__config.key_error.call(key) if not key?(key)

      super(key)
    end
def [](input)
      key = __convert_key(input)
      return @__config.key_error.call(key) if not key?(key)

      super(key)
    end
Hash Overridden Methods (for string & symbol indifferent access)