Make the packet work on Python 3.7

[asvetlov]

No description provided.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@65bb3dc). Click here to learn what that means.
The diff coverage is 100%.

@@            Coverage Diff            @@
##             master     #402   +/-   ##
=========================================
  Coverage          ?   92.75%           
=========================================
  Files             ?       30           
  Lines             ?     1766           
  Branches          ?      191           
=========================================
  Hits              ?     1638           
  Misses            ?      110           
  Partials          ?       18

Impacted Files	Coverage Δ
python/neuromation/cli/login.py	93.65% <100%> (ø)
python/neuromation/clientv2/api.py	97.91% <100%> (ø)
python/neuromation/clientv2/utils.py	100% <100%> (ø)

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