# File lib/soap/generator.rb, line 220
  def self.assign_ns(attrs, ns, namespace, tag = nil)
    if namespace.nil?
      raise FormatEncodeError.new("empty namespace")
    end
    override_default_ns = (tag == '' and namespace != ns.default_namespace)
    if override_default_ns or !ns.assigned?(namespace)
      assign_ns!(attrs, ns, namespace, tag)
    end
  end