+ * If 'value_type' is OVSDB_TYPE_VOID and 'n_min' or 'n_max' (or both) has a
+ * value other than 1, then the type is a set of 'key_type'. If 'n_min' is 0
+ * and 'n_max' is 1, then the type can also be considered an optional
+ * 'key_type'.
+ *
+ * If 'value_type' is not OVSDB_TYPE_VOID, then the type is a map from
+ * 'key_type' to 'value_type'. If 'n_min' is 0 and 'n_max' is 1, then the type
+ * can also be considered an optional pair of 'key_type' and 'value_type'.