>> require "hpricot" => true >> doc = Hpricot('') {} => #<Hpricot::Doc> >> doc.head('') ArgumentError: block not supplied from /usr/local/ruby-1.8.7/lib/ruby/gems/1.8/gems/hpricot-0.8.2/lib/hpricot/builder.rb:159:in `instance_eval' from /usr/local/ruby-</hpricot::doc>…