@property
    def page_width(self):
        pgSz = self.pgSz
        if pgSz is None:
            return None
        return pgSz.w
create a new set of grouped files
dataset/ETHPy150Open python-openxml/python-docx/docx/oxml/section.py/CT_SectPr.page_width--crossover with--dataset/ETHPy150Open Mouse-Imaging-Centre/pydpiper/atoms_and_modules/registration_file_handling.py/RegistrationPipeFH.newGroup