+ Hash#transform_keys (incomplete).
+ Hash#transform_keys (incomplete).

See https://bugs.ruby-lang.org/issues/13583#note-8

ruby/spec,ruby/spec,ruby/rubyspec,nobu/rubyspec,eregon/rubyspec,nobu/rubyspec,ruby/rubyspec,nobu/rubyspec,eregon/rubyspec,eregon/rubyspec,ruby/spec