+/**
+ * modest_text_utils_remove_duplicate_addresses_list
+ * @address_list: non-NULL #GSList of email addresses
+ *
+ * remove duplicate addresses from a list of email addresses
+ *
+ * Returns: a list without the duplicate addresses or NULL in case of
+ * error or the original @address_list was NULL
+ */
+GSList *modest_text_utils_remove_duplicate_addresses_list (GSList *address_list);
+