AttributeError: 'FileDataset' object has no attribute 'dcm_image'

I am trying to create 3D volumes out of DICOM images but I am facing errors:
AttributeError Traceback (most recent call last)
in ()
10 slices=[dicom.read_file(path+’/’+s,force=True) for s in CT_images]
11
—> 12 slices=sorted(slices,key=lambda x:x.dcm_image.ImagePositionPatient[2])
13
14 pixel_spacing=slices[0].pixel_spacing

1 frames
/usr/local/lib/python3.6/dist-packages/pydicom/dataset.py in getattr(self, name)
776 return {}
777 # Try the base class attribute getter (fix for issue 332)
–> 778 return object.getattribute(self, name)
779
780 @property

AttributeError: ‘FileDataset’ object has no attribute ‘dcm_image’