for color, code in pairs(rgb_colors) do   -- 'rgb_colors' is a table with color string names as keys and the corresponding string codes as values
	minetest.register_node("luxury_decor:simple_" .. color .. "_tulle_with_rings_leftmove", {  -- an error is starting from here
		description = "Simple " .. string.upper(string.sub(color, 1, 1) .. string.sub(color, 2) .. " Tulle With Rings (left-moving)\n".. minetest.colorize("#FF0000", "Right-click the bottom of a cornice to connect with it")),
		drawtype="mesh",
		mesh = "simple_tulle_with_rings_leftmove.b3d",
		tiles = {
			{"simple_tulle_moving2.png", animation={
				type="vertical_frames",
				aspect_w=64,
				aspect_h=64,
				length=1.5
				}
			}
		},
		overlay_tiles = {{"simple_tulle_moving1.png", color=code}},
		use_texture_alpha = true,
		paramtype = "light",
		paramtype2 = "facedir",
		walkable = false,
		collision_box = {
			type="fixed",
			fixed = {
				{-0.5, -0.5, 0.25, 0.5, 0.5, 0.5}
			}
		},
		selection_box = {
			type="fixed",
			fixed = {
				{-0.5, -0.5, 0.25, 0.5, 0.5, 0.5}
			}
		},
		groups = {snappy=3.7, not_in_creative_inventory=true},
		sounds = default.node_sound_leaves_defaults(),
		node_group = "Curtain with rings",
		sub_node_group = "Left-Moving"
	})
end