Error accessing one ROI name

Code and error message are shown below. Other ROI name is fine so far. Any help? Thanks.

dicom_dir = f"./dicom/Renamed/Pediatric-CT-SEG-028C9198/"
rt_file = f"{dicom_dir}/Mask/1-1.dcm"
rtstruct = RTStructBuilder.create_from(
    dicom_series_path=dicom_dir+"Image/", 
    rt_struct_path=rt_file
    )
names = rtstruct.get_roi_names()
print(names)
mask_3d = rtstruct.get_roi_mask_by_name("Breast Left")
first_mask_slice = mask_3d[:, :, 1]
plt.imshow(first_mask_slice) # View one slice within the mask
plt.show()

['Adrenal Left', 'Adrenal Right', 'Bladder', 'Breast Left', 'Breast Right', 'Duodenum', 'Esophagus', 'Femoral Head Lef', 'Femoral Head Rig', 'Gall Bladder', 'Gonads', 'Heart', 'Kidney Left', 'Kidney Right', 'Large Intestine', 'Liver', 'Pancreas', 'Prostate', 'Rectum', 'Small Intestine', 'Spinal Canal', 'Spleen', 'Stomach', 'Thymus', 'UteroCervix', 'Lung_L', 'Lung_R', 'Skin', 'Bones']
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
d:\PythonProjects\AI_Segmention_Pediatric_Organ\step0_clean_names.ipynb Cell 9 in <cell line: 9>()
      [7](vscode-notebook-cell:/d%3A/PythonProjects/AI_Segmention_Pediatric_Organ/step0_clean_names.ipynb#X16sZmlsZQ%3D%3D?line=6) names = rtstruct.get_roi_names()
      [8](vscode-notebook-cell:/d%3A/PythonProjects/AI_Segmention_Pediatric_Organ/step0_clean_names.ipynb#X16sZmlsZQ%3D%3D?line=7) print(names)
----> [9](vscode-notebook-cell:/d%3A/PythonProjects/AI_Segmention_Pediatric_Organ/step0_clean_names.ipynb#X16sZmlsZQ%3D%3D?line=8) mask_3d = rtstruct.get_roi_mask_by_name("Breast Left")
     [10](vscode-notebook-cell:/d%3A/PythonProjects/AI_Segmention_Pediatric_Organ/step0_clean_names.ipynb#X16sZmlsZQ%3D%3D?line=9) first_mask_slice = mask_3d[:, :, 1]
     [11](vscode-notebook-cell:/d%3A/PythonProjects/AI_Segmention_Pediatric_Organ/step0_clean_names.ipynb#X16sZmlsZQ%3D%3D?line=10) plt.imshow(first_mask_slice) # View one slice within the mask

File d:\python38\lib\site-packages\rt_utils\rtstruct.py:110, in RTStruct.get_roi_mask_by_name(self, name)
    108 for structure_roi in self.ds.StructureSetROISequence:
    109     if structure_roi.ROIName == name:
--> 110         contour_sequence = ds_helper.get_contour_sequence_by_roi_number(
    111             self.ds, structure_roi.ROINumber
    112         )
    113         return image_helper.create_series_mask_from_contour_sequence(
    114             self.series_data, contour_sequence
    115         )
    117 raise RTStruct.ROIException(f"ROI of name `{name}` does not exist in RTStruct")

File d:\python38\lib\site-packages\rt_utils\ds_helper.py:221, in get_contour_sequence_by_roi_number(ds, roi_number)
    217 for roi_contour in ds.ROIContourSequence:
    218 
    219     # Ensure same type
    220     if str(roi_contour.ReferencedROINumber) == str(roi_number):
--> 221         return roi_contour.ContourSequence
    223 raise Exception(f"Referenced ROI number '{roi_number}' not found")

File d:\python38\lib\site-packages\pydicom\dataset.py:834, in Dataset.__getattr__(self, name)
    832     return {}
    833 # Try the base class attribute getter (fix for issue 332)
--> 834 return object.__getattribute__(self, name)

AttributeError: 'Dataset' object has no attribute 'ContourSequence'

Reproduce the supplied example with the referenced DICOM series, then inspect rt_utils/rtstruct.py and rt_utils/ds_helper.py around get_roi_mask_by_name and get_contour_sequence_by_roi_number. Determine why the reported ROI reaches a Dataset without ContourSequence and add or document handling that matches the library's expected RTSTRUCT data; verify the reported ROI can be processed without the shown AttributeError.