from diffusers import AutoPipelineForText2Image
import torch

pipeline = AutoPipelineForText2Image.from_pretrained('black-forest-labs/FLUX.1-dev', torch_dtype=torch.bfloat16).to('cuda')
pipeline.load_lora_weights('busetolunay/bc1k-background-flux1', weight_name='backgrounds_flux1.safetensors')
image = pipeline('bc1@k style. A temple town built around a three-tier pagoda with upswept tiled roofs, approached through two torii gates along a lantern-lined path. A tea house with a curved roof sits beside a koi pond crossed by an arched wooden bridge at the front, with stone lanterns and cherry trees framing the walkways. Rows of low wooden shops with sloped roofs line the street on the left, and a bell tower stands on a stone platform on the right. Forested hills rise behind the rooftops.').images[0]
image.save("my_image.png")

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