fails:A Proc taking |(a, b)| arguments raises an TypeError if #to_ary does not return an Array
fails:A Proc taking |(a, b)| arguments calls #to_ary to convert a single passed object to an Array
fails:A Proc taking |(a, b)| arguments raises a TypeError if #to_ary does not return an Array
fails:A Proc taking |(a, b)| arguments raises a TypeError if #to_ary does not return an Array
