Attributes encompass the core information about a particular TargetingIdea. Some
attributes are for
IdeaTypes, some are for
IdeaTypes, and some are for both. Ultimately, an Attribute instance simply wraps
an actual value of interest. For example, KeywordAttribute wraps the keyword itself,
while a BooleanAttribute simply wraps a boolean describing some information about the
Indicates that this instance is a subtype of Attribute. Although this field is returned in the response, it is ignored on input and cannot be selected. Specify xsi:type instead.