Reverse of concatenation in a specific dimension

I am working with vision transformer (ViT). In one of its steps, the class token is concatenated with the tensor in a specific dimension (dim=1) and I want to remove the class token that had been concatenated. How I can do this?

batch_class_token = self.class_token.expand(n, -1, -1)
x =[batch_class_token, x], dim=1)