fix lint error

[yufeiminds]

No description provided.

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@278ab03). Click here to learn what that means.
The diff coverage is 100%.

@@            Coverage Diff            @@
##             master      #11   +/-   ##
=========================================
  Coverage          ?   97.24%           
=========================================
  Files             ?       18           
  Lines             ?      508           
  Branches          ?        0           
=========================================
  Hits              ?      494           
  Misses            ?       14           
  Partials          ?        0

Impacted Files	Coverage Δ
ucloud/core/typesystem/schema.py	100% <100%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 278ab03...2faf251. Read the comment docs.