Completes 2.10 - 2.12 exercises on Cold Closures Cove

Signed-off-by: Irina Chichikova <diva.artim@gmail.com>
Completes 2.14, 2.15 exercises on Cold Closures Cove

Signed-off-by: Irina Chichikova <diva.artim@gmail.com>