Modify the implementation of retrieve_timesteps in CogView4-Control.

src/diffusers/pipelines/cogview4/pipeline_cogview4_control.py

@@ -68,7 +68,7 @@ def calculate_shift(
     return mu
 
 
-# Copied from diffusers.pipelines.stable_diffusion.pipeline_stable_diffusion.retrieve_timesteps
+# Copied from diffusers.pipelines.cogview4.pipeline_cogview4.retrieve_timesteps
 def retrieve_timesteps(
     scheduler,
     num_inference_steps: Optional[int] = None,
@@ -100,10 +100,19 @@ def retrieve_timesteps(
         `Tuple[torch.Tensor, int]`: A tuple where the first element is the timestep schedule from the scheduler and the
         second element is the number of inference steps.
     """
+    accepts_timesteps = "timesteps" in set(inspect.signature(scheduler.set_timesteps).parameters.keys())
+    accepts_sigmas = "sigmas" in set(inspect.signature(scheduler.set_timesteps).parameters.keys())
+
     if timesteps is not None and sigmas is not None:
-        raise ValueError("Only one of `timesteps` or `sigmas` can be passed. Please choose one to set custom values")
-    if timesteps is not None:
-        accepts_timesteps = "timesteps" in set(inspect.signature(scheduler.set_timesteps).parameters.keys())
+        if not accepts_timesteps and not accepts_sigmas:
+            raise ValueError(
+                f"The current scheduler class {scheduler.__class__}'s `set_timesteps` does not support custom"
+                f" timestep or sigma schedules. Please check whether you are using the correct scheduler."
+            )
+        scheduler.set_timesteps(timesteps=timesteps, sigmas=sigmas, device=device, **kwargs)
+        timesteps = scheduler.timesteps
+        num_inference_steps = len(timesteps)
+    elif timesteps is not None and sigmas is None:
         if not accepts_timesteps:
             raise ValueError(
                 f"The current scheduler class {scheduler.__class__}'s `set_timesteps` does not support custom"
@@ -112,9 +121,8 @@ def retrieve_timesteps(
         scheduler.set_timesteps(timesteps=timesteps, device=device, **kwargs)
         timesteps = scheduler.timesteps
         num_inference_steps = len(timesteps)
-    elif sigmas is not None:
-        accept_sigmas = "sigmas" in set(inspect.signature(scheduler.set_timesteps).parameters.keys())
-        if not accept_sigmas:
+    elif timesteps is None and sigmas is not None:
+        if not accepts_sigmas:
             raise ValueError(
                 f"The current scheduler class {scheduler.__class__}'s `set_timesteps` does not support custom"
                 f" sigmas schedules. Please check whether you are using the correct scheduler."
@@ -515,7 +523,7 @@ def __call__(
                 The output format of the generate image. Choose between
                 [PIL](https://pillow.readthedocs.io/en/stable/): `PIL.Image.Image` or `np.array`.
             return_dict (`bool`, *optional*, defaults to `True`):
-                Whether or not to return a [`~pipelines.stable_diffusion_xl.StableDiffusionXLPipelineOutput`] instead
+                Whether or not to return a [`~pipelines.pipeline_CogView4.CogView4PipelineOutput`] instead
                 of a plain tuple.
             attention_kwargs (`dict`, *optional*):
                 A kwargs dictionary that if specified is passed along to the `AttentionProcessor` as defined under
@@ -533,8 +541,6 @@ def __call__(
             max_sequence_length (`int`, defaults to `224`):
                 Maximum sequence length in encoded prompt. Can be set to other values but may lead to poorer results.
 
-        Examples:
-
         Returns:
             [`~pipelines.cogview4.pipeline_CogView4.CogView4PipelineOutput`] or `tuple`:
             [`~pipelines.cogview4.pipeline_CogView4.CogView4PipelineOutput`] if `return_dict` is True, otherwise a