Attribute merging strategy that joins all the individual elements of both attribute values in a single array. When
merging two attributes, attribute values that are not arrays are converted to an array whose value is a sequence
with a single element: the value of the attribute prior to the conversion.
Attribute merging strategy that joins all the individual elements of both attribute values in a single array. When merging two attributes, attribute values that are not arrays are converted to an array whose value is a sequence with a single element: the value of the attribute prior to the conversion.