Can't call index?

Isn’t this an index or am I just doing it wrong?
(To run the script you’ll need two clips in the vse with a cross transition between them)

import bpy

seq_strips = bpy.context.scene.sequence_editor.sequences

for strip in seq_strips:
    
    if strip.type in ['CROSS']: 
        
        try:
            next_element = seq_strips[seq_strips.index(strip)+1]
        except (ValueError,IndexError):
            next_element = "" 
        print ("Current: "+strip.bpy.path.basename(strip.filepath) )   
        print ("Next: "+next_element.bpy.path.basename(strip.filepath))