" element. ]]> ..." element. ]]> ". ]]> ..." element. ]]> ". ]]> Denotes a Python None value. Necessary because an empty "value" tag will resolve to an empty String, which will not be resolved to a None value unless a special PropertyEditor does so. This type represents ALL collection elements. This type represents collection elements that are indexable, able to be stored inside a set (non-mutable).