collect_attrs

# File lib/rss/rss.rb, line 1036
    def collect_attrs
      attrs = {}
      _attrs.each do |name, required, alias_name|
        value = __send__(alias_name || name)
        return nil if required and value.nil?
        next if value.nil?
        return nil if attrs.has_key?(name)
        attrs[name] = value
      end
      attrs
    end