How to get all file-size in a MPV playlist then add them up?

Using this function I am able to get the file-size of the current playing file in the playlist of MPV media player. But I also want to be able to get file_size of all files in the playlist and get the total sum of that and write it to the screen once I press a hot-key. I would appreciate any help as I think I am almost there but I am a bit stuck on what to do from here on

local assdraw = require "mp.assdraw"
local options = require "mp.options"
local mp = require 'mp'
local utils = require "mp.utils"

package.path = mp.command_native({"expand-path", "~~/script-modules/?.lua;"})..package.path
local filesize = require "filesize"

local function readable_bytes(size) 
    if not size then return nil end
    return filesize(size)
    
end
local info_active = true
local o = {
    font_size = 9.25,
    font_color = "FFFFFF",
    border_size = 0.8,
    border_color = "000000",
    font_name = "Source Sans Pro"
}
options.read_options(o)
function get_formatting()
    return string.format(
        "{\\fs%d}{\\1c&H%s&}{\\bord%f}{\\3c&H%s&}{\\fn%s}",
        o.font_size, o.font_color, o.border_size, o.border_color, o.font_name
    )
end

function get_info()
       return string.format(
           "Dotta: %s %s",
           get_formatting(),
           display_total_playlist_filesize())
   end

function render_info()
    ass = assdraw.ass_new()
    ass:pos(10, 10)
    ass:append(get_info())
    mp.set_osd_ass(0, 0, ass.text)
end

function clear_info()
    mp.set_osd_ass(0, 0, "") 
end   
   
function toggle_info()
    if info_active then
        mp.register_event("tick", render_info)
        render_info()
    
    else
        -- TODO: Rewrite to timer + pause/unpause handlers.
        mp.unregister_event(render_info)
        clear_info()
    end
    info_active = not info_active
end

function display_total_playlist_filesize() 

    file_size = mp.get_property_native('file-size')

    if not file_size then return nil end
    
    return string.format("%s", readable_bytes(file_size)
)
end


mp.add_key_binding("TAB", "toggle_info", toggle_info)