from diffusers import AutoPipelineForText2Image
import torch
pipeline = AutoPipelineForText2Image.from_pretrained('alvdansen/pola-photo-flux', torch_dtype=torch.float16).to('cuda')
pipeline.load_lora_weights('codermert/demomannn_flux', weight_name='flux_train_replicate.safetensors')
image = pipeline('your prompt').images[0]

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