# File lib/nokogiri/xml/node_set.rb, line 214 def attr key, value = nil, &blk unless Hash === key || key && (value || blk) return first.attribute(key) end hash = key.is_a?(Hash) ? key : { key => value } hash.each { |k,v| each { |el| el[k] = v || blk[el] } } self end