choose a field type to sort a list

Hi !

' pseudo code 
Type TPix
  field x : int
  field y : int
End type

Global Pixels_list = createlist()

Function Create:TPix (x,y)
	
	Local p:TPix = New TPix
	p.x = x
	p.y = y
	ListAddlast Pixels_list, p
	Return p
		
End Function

How to sort Pixels_list items by 'y' ascending ?
i don't understand how to use sortlist !
Thanks !