cheduler: DDPMScheduler image_noising_scheduler: DDPMScheduler safety_checker: Optional feature_extractor: Optional watermarker: Optional requires_safety_checker: bool = True  )     __call__  < source > ( prompt: Union = None height: int = None width: int = None image: Union = None num_inference_steps: int = 50 timesteps: List = None guidance_scale: float = 4.0 negative_prompt: Union = None num_images_per_prompt: Optional = 1 eta: float = 0.0 g