Isa_btree__Isa_btree_intf.Leaf_node_frame_map_ops_type
type ('k, 'v, 't) map_ops
= ('k, 'v, 't) Tjr_lib_core.Tjr_map.With_base_as_record.map_ops
To avoid dependency on any particular map implementation, we define the exact interface we require here.