Problem with using code from godot 3.x to 4.1.1 with connect()

[alexander the great]

I am trying to make a multiplayer 2D shooter following a tutorial but the tutorial is using version 3.2.3. The code in version 3.2.3 is:

extends Control

@onready var multiplayer_config_ui = $Multiplayer_configure
@onready var server_ip_address = $Multiplayer_configure/Server_ip_address

@onready var device_ip_address = $CanvasLayer/Device_ip_address

func _ready() -> void:
	get_tree().connect("network_peer_connected", self, "_player_connected")
	get_tree().connect("network_peer_disconnected", self, "_player_disconnected")
	get_tree().connect("connected_to_server", self, "_connected_to_server")
	
	device_ip_address = Network.ip_address
	
func _player_connected(id) -> void:
	print("Player " + str(id) + " has connected")

func _player_disconnected(id) -> void:
	print("Player " + str(id) + " has disconnected")
	
func _on_create_server_pressed():
	multiplayer_config_ui.hide()
	Network.create_server()

func _on_join_server_pressed():
	if server_ip_address.text != "":
		multiplayer_config_ui.hide()
		Network.ip_address = server_ip_address.text_changed
		Network.join_server()

however I get the error:
Line 9:Invalid argument for "connect()" function: argument 2 should be "Callable" but is "res://Network_setup.gd".
Line 9:Cannot pass a value of type "String" as "int".
Line 9:Invalid argument for "connect()" function: argument 3 should be "int" but is "String".

on lines 9, 10 and 11. I have seen some other ways people have fixed it with timers but don't know how they would apply to this:
Gdscript connect() function

[sepTN]

What version you are currently using to follow along the tutorial?

The difference between Godot 3 and Godot 4 in terms of signal connecting is that in Godot 4 it's no longer necessary to use string, but the identifier itself. So normally:

In Godot 3:

	get_tree().connect("network_peer_connected", self, "_player_connected")
	get_tree().connect("network_peer_disconnected", self, "_player_disconnected")
	get_tree().connect("connected_to_server", self, "_connected_to_server")

In Godot 4:

	get_tree().network_peer_connected.connect(_player_connected)
	get_tree().network_peer_disconnected.connect(_player_disconnected)
	get_tree().connected_to_server.connect(_connected_to_server)

---

But then again you can't really use it since they have completely reworked multiplayer from Godot 3 -> Godot 4. And network_peer_connected, network_peer_disconnected, connected_to_server, are no longer signals of get_tree()

[alexander the great]

I'm using 4.1.1 stable,

	get_tree().network_peer_connected.connect(_player_connected)
	get_tree().network_peer_disconnected.connect(_player_disconnected)
	get_tree().connected_to_server.connect(_connected_to_server)

the first 2 lines seem to have worked (weirdly) and yes I get the error:
Line 11:Identifier "_connected_to_server" not declared in the current scope.

What could I use to get around this problem?

This is the tutorial I'm following:
Godot 3 Networked Multiplayer Shooter Tutorial