1 # A document may be null. 2 --- 3 --- 4 # This mapping has four keys, 5 # one has a value. 6 empty: 7 canonical: ~ 8 english: null 9 ~: null key 10 --- 11 # This sequence has five 12 # entries, two have values. 13 sparse: 14 - ~ 15 - 2nd entry 16 - 17 - 4th entry 18 - Null 19
