Tornado import error: 'no named module singledispatch'

Question

After I installed tornado, upon testing an instance, it shows the error no module named singledispatch.

But when I import tornado it's ok.

Need help.

Answer 1

Somehow you installed Tornado without its required dependencies. Install them with:

python -m pip install singledispatch backports_abc

Here's the list of new dependencies in Tornado 4.3.