# File lib/iq_rdf/document.rb, line 30
    def namespaces(namespaces)
      raise ArgumentError, "Parameter 'namespaces' has to be a hash" unless namespaces.is_a?(Hash)

      namespaces.each do |name, uri_prefix|
        uri_prefix = ::URI.parse(uri_prefix)
        raise ArgumentError, "Parameter 'namespaces' must be im the form {Symbol => URIString, ...}" unless name.is_a? Symbol

        register_namespace(name, uri_prefix)
      end
      self
    end