library implements for all the pipelines (such as downloading or saving, running on a particular device, etc.)  __call__  < source > ( prompt: List reference_image: Image condtioning_image: Image source_subject_category: List target_subject_category: List latents: Optional = None guidance_scale: float = 7.5 height: int = 512 width: int = 512 num_inference_steps: int = 50 generator: Union = None neg_prompt: Optional = '' prompt_strength: float = 1.0 prompt_reps: int = 20 output_type: Optional = 'pil' return_dict: bool = True  ) → ImagePipelineOutput or tuple  Parameters   prompt (List[str]) —