Ruby/Hash/has value

hash = {}
1.upto(10) { |x| hash[x] = x * x }
hash.has_value? 49                   # => true
hash.has_value? 81                   # => true
hash.has_value? 50                   # => false

zip = { 1 => "One", 2 => "Two", 3 => "Three",
4 => "Four", 5 => "Five", 6 => "Six", 7 =>
"Seven", 8 => "Eight", 9 => "Eight" }
zip.has_value? "One" # => true