How about this?
import torch
device = torch.device("mps" if torch.backends.mps.is_available() else "cpu")
prompt = "A cat holding a sign that says hello world"
pipe.to(device)
image = pipe(
prompt,
height=1024,
width=1024,
guidance_scale=3.5,
num_inference_steps=1,
max_sequence_length=512,
generator=torch.Generator(device).manual_seed(0)
).images[0]
image.save("flux-dev.png")