def body
      fetch_body unless fetched?
      raise NoOpenGraphDataError, "No response body received for #{@uri}" if fetch_failed?
      raise NoOpenGraphDataError, "Did not receive a HTML site at #{@uri}" unless html?
      @get_response.body
    end
def body
      fetch_body unless fetched?
      raise NoOpenGraphDataError, "No response body received for #{@uri}" if fetch_failed?
      raise NoOpenGraphDataError, "Did not receive a HTML site at #{@uri}" unless html?
      @get_response.body
    end
Retrieve the body

 @todo Custom error class
 @raise [ArgumentError] The received content does not seems to be HTML.
 @return [String]