[Bug] TypeError: 'NoneType' object is not iterable

[Priyanshu88]

Describe the bug

The full traceback is below:
runner = Runner.from_cfg(cfg)
File "/opt/conda/lib/python3.9/site-packages/mmengine/runner/runner.py", line 462, in from_cfg
runner = cls(
File "/opt/conda/lib/python3.9/site-packages/mmengine/runner/runner.py", line 429, in init
self.model = self.build_model(model)
File "/opt/conda/lib/python3.9/site-packages/mmengine/runner/runner.py", line 836, in build_model
model = MODELS.build(model)
File "/opt/conda/lib/python3.9/site-packages/mmengine/registry/registry.py", line 570, in build
return self.build_func(cfg, *args, **kwargs, registry=self)
File "/opt/conda/lib/python3.9/site-packages/mmengine/registry/build_functions.py", line 232, in build_model_from_cfg
return build_from_cfg(cfg, registry, default_args)
File "/opt/conda/lib/python3.9/site-packages/mmengine/registry/build_functions.py", line 121, in build_from_cfg
obj = obj_cls(**args) # type: ignore
File "/mmrazor/mmrazor/implementations/pruning/group_fisher/algorithm.py", line 57, in init
self.mutator.prepare_from_supernet(self.architecture)
File "/mmrazor/mmrazor/models/mutators/channel_mutator/channel_mutator.py", line 113, in prepare_from_supernet
units = self._prepare_from_tracer(supernet, self.parse_cfg)
File "/mmrazor/mmrazor/models/mutators/channel_mutator/channel_mutator.py", line 311, in _prepare_from_tracer
unit_configs = tracer.analyze(model)
File "/mmrazor/mmrazor/models/task_modules/tracer/channel_analyzer.py", line 107, in analyze
fx_graph = self._fx_trace(model)
File "/mmrazor/mmrazor/models/task_modules/tracer/channel_analyzer.py", line 132, in _fx_trace
args = self.demo_input.get_data(model)
File "/mmrazor/mmrazor/models/task_modules/demo_inputs/demo_inputs.py", line 34, in get_data
data = self._get_data(model, input_shape, training)
File "/mmrazor/mmrazor/models/task_modules/demo_inputs/default_demo_inputs.py", line 108, in _get_data
return defaul_demo_inputs(model, input_shape, training, self.scope)
File "/mmrazor/mmrazor/models/task_modules/demo_inputs/default_demo_inputs.py", line 79, in defaul_demo_inputs
return demo_input().get_data(model, input_shape, training)
File "/mmrazor/mmrazor/models/task_modules/demo_inputs/demo_inputs.py", line 34, in get_data
data = self._get_data(model, input_shape, training)
File "/mmrazor/mmrazor/models/task_modules/demo_inputs/demo_inputs.py", line 57, in _get_data
data = self._get_mm_data(model, input_shape, training)
File "/mmrazor/mmrazor/models/task_modules/demo_inputs/demo_inputs.py", line 63, in _get_mm_data
data = model.data_preprocessor(data, training)
File "/opt/conda/lib/python3.9/site-packages/torch/nn/modules/module.py", line 1190, in _call_impl
return forward_call(*input, **kwargs)
File "/opt/conda/lib/python3.9/site-packages/mmpose/models/data_preprocessors/data_preprocessor.py", line 94, in forward
for data_sample, pad_shape in zip(data_samples, batch_pad_shape):

To Reproduce

Just run the train.py having rtmo_s with coco dataset format on body_2d_keypoint by using the pruning method.

Post related information

i have done all the relevant changes in config data and metafile to run this successfully but failure persists.

Additional context

Add any other context about the problem here.

[here]