+bool psi_plist_del_r(struct psi_plist *list, size_t offset_start, size_t offset_end, void **eles);
+struct psi_plist *psi_plist_ins(struct psi_plist *list, size_t index, void *ptr);
+struct psi_plist *psi_plist_ins_r(struct psi_plist *list, size_t offset_start, size_t num_eles, void **eles);
+