Any way to save Arrays?

Trying to make a leaderboard system that takes in past high scores. Only everytime it saves a new high, the game crashes and I get an error, "Invalid operands 'int' and 'Nil' in operator '>' "

This is my save data script:

extends Node

var save_path = "user://varible.save"

var PersBest = 0

var highScores = [10000, 8000, 6000, 3000, 2000]

# Called when the node enters the scene tree for the first time.

func _ready() -> void:

Load()

# Called every frame. 'delta' is the elapsed time since the previous frame.

func _process(delta: float) -> void:

pass

func Save():

var file = FileAccess.open(save\_path, FileAccess.WRITE)

file.store\_var(PersBest)

file.store\_var(highScores)

func Load():

if FileAccess.file\_exists(save\_path):

	var file = FileAccess.open(save\_path, FileAccess.READ)

	PersBest = file.get\_var(PersBest)

	highScores\[0\] = file.get\_var(highScores\[0\])

	highScores\[1\] = file.get\_var(highScores\[1\])

	highScores\[2\] = file.get\_var(highScores\[3\])

	highScores\[3\] = file.get\_var(highScores\[3\])

	highScores\[4\] = file.get\_var(highScores\[4\])

else:

	Save()

And this is the function in player script where the error occurs:

func _on_kill_timer_timeout() -> void:

Autoload.playing = false

if Autoload.score > SaveData.PersBest:

	SaveData.PersBest = Autoload.score

if Autoload.score > SaveData.highScores\[-1\]:

	SaveData.highScores\[-1\] = Autoload.score

	SaveData.highScores.sort()

SaveData.Save()

queue\_free()

Help is appreciated