Check if variable is already defined

Use try … except for NameError for catch the definition error

        try:
            wb2
        except NameError:
            wb2 = load_workbook(
                filename='C:\\Users\\KaiyiLin\\Documents\\Alex\\Boehringer\\check_relation\\SystemOrg_Template.xlsx',
                # profile 的文件地址， title和HC Code
                read_only=True)