Minist error Dataset not found

I have download the mnist but has the error,like this:

Traceback (most recent call last):
File “404_autoencoder.py”, line 36, in
download=DOWNLOAD_MNIST, # download it if you don’t have it
File “/home/jackie/miniconda3/lib/python3.6/site-packages/torchvision/datasets/mnist.py”, line 36, in init
’ You can use download=True to download it’)
RuntimeError: Dataset not found. You can use download=True to download it

RuntimeError: Dataset not found. You can use download=True to download it

When I want to use pytorch download MNIST data sets, always appear

"Download = True)
File “/usr/local/lib/python2.7/dist-packages/torchvision/datasets/mnist.py”, line 45, in init
self.download ()
File “/usr/local/lib/python2.7/dist-packages/torchvision/datasets/mnist.py”, line 119, in download
out_f.write (zip_f.read ())
File “/usr/lib/python2.7/gzip.py”, line 261, in read
self._read (readsize)
File “/usr/lib/python2.7/gzip.py”, line 303, in _read
self._read_gzip_header ()
File “/usr/lib/python2.7/gzip.py”, line 197, in _read_gzip_header
raise IOError, 'Not a gzipped file’
IOError: Not a gzipped file "