godot how to make a specific signal take place fitst code example

Example 1: custom signal godot

extends Node2D


signal my_signal


func _ready():
    emit_signal("my_signal")

Example 2: godot connect signal code

extends Node2D


func _ready():
    $Timer.connect("timeout", self, "_on_Timer_timeout")


func _on_Timer_timeout():
    $Sprite.visible = !$Sprite.visible