library implements for all the pipelines (such as downloading or saving, running on a particular device, etc.)  __call__  < source > ( prompt: Union image: Union negative_prompt: Union = None num_inference_steps: int = 100 guidance_scale: float = 4.0 num_images_per_prompt: int = 1 strength: float = 0.3 height: int = 512 width: int = 512 prior_guidance_scale: float = 4.0 prior_num_inference_steps: int = 25 generator: Union = None latents: Optional = None output_type: Optional = 'pil' callback: Optional = None callback_steps: int = 1 return_dict: bool = True  ) → ImagePipelineOutput or tuple  Parameters   prompt (str or List[str]) —