03_linear_regression_sol.py can't run with errors as follows

[WoNiuHu]

Traceback (most recent call last): File "D:/stanford_tensorflow_tutorials/tf_oreilly/01_linear_regression_sol.py", line 19, in book = xlrd.open_workbook(DATA_FILE, encoding_override="utf-8") File "C:\Anaconda3\lib\site-packages\xlrd_init_.py", line 441, in open_workbook ragged_rows=ragged_rows, File "C:\Anaconda3\lib\site-packages\xlrd\book.py", line 107, in open_workbook_xls bk.fake_globals_get_sheet() File "C:\Anaconda3\lib\site-packages\xlrd\book.py", line 687, in fake_globals_get_sheet self.get_sheets() File "C:\Anaconda3\lib\site-packages\xlrd\book.py", line 678, in get_sheets self.get_sheet(sheetno) File "C:\Anaconda3\lib\site-packages\xlrd\book.py", line 669, in get_sheet sh.read(self) File "C:\Anaconda3\lib\site-packages\xlrd\sheet.py", line 1475, in read self.update_cooked_mag_factors() File "C:\Anaconda3\lib\site-packages\xlrd\sheet.py", line 1543, in update_cooked_mag_factors elif not (10 <= zoom <= 400): TypeError: unorderable types: int() <= NoneType()