from diffusers import AutoPipelineForText2Image
import torch

pipeline = AutoPipelineForText2Image.from_pretrained('black-forest-labs/FLUX.1-schnell', torch_dtype=torch.bfloat16).to('cuda')
pipeline.load_lora_weights('dhanushreddy29/tshirt-design-2', weight_name='tshirt-design-2.safetensors')
image = pipeline('tshirt design, a cat with sunglasses lounging on a hammock with text 'Purr-fect Vacation' in a playful font. tdsgn').images[0]
image.save("my_image.png")

For more details, including weighting, merging and fusing LoRAs, check the documentation on loading LoRAs in diffusers