get_acceptable (OpenID::Yadis)

    # File lib/openid/yadis/accept.rb, line 132
        def self.get_acceptable(accept_header, have_types)
          # Parse the accept header and return a list of available types
          # in preferred order. If a type is unacceptable, it will not be
          # in the resulting list.
          #
          # This is a convenience wrapper around matchTypes and
          # parse_accept_header
          #
          # (str, [str]) -> [str]
          accepted = self.parse_accept_header(accept_header)
          preferred = self.match_types(accepted, have_types)
          return preferred.collect { |mtype, _| mtype }
        end