theano 报错ImportError: cannot import name 'downsample'

The error ImportError: cannot import name 'downsample' is reported, which is mainly caused by the update of Theano version. The solution is

pip install theano==0.8.2
pip install lasagne==0.1 It doesn't matter if you run this command and report an error

Then try your program again and find that there is no such problem.