frozen / hash / key / ruby / rubyspec / stringHash usa chave String congeladastr = 'str'{str => 1}.key(1).eql? str #=> true{str => 1}.key(1).equal? str #=> falsestr = 'str'.freeze{str => 1}.key(1).eql? str #=> true{str => 1}.key(1).equal? str #=> trueRubySpec