Undefined name: from io import BytesIO for line 178

[cclauss]

flake8 testing of https://github.com/QuantStack/voila on Python 3.7.1

$ flake8 . --count --select=E9,F63,F72,F82 --show-source --statistics

./setup.py:177:15: F821 undefined name 'BytesIO'
        buf = BytesIO()
              ^
1     F821 undefined name 'BytesIO'
1

E901,E999,F821,F822,F823 are the "showstopper" flake8 issues that can halt the runtime with a SyntaxError, NameError, etc. These 5 are different from most other flake8 issues which are merely "style violations" -- useful for readability but they do not effect runtime safety.

• F821: undefined name name
• F822: undefined name name in __all__
• F823: local variable name referenced before assignment
• E901: SyntaxError or IndentationError
• E999: SyntaxError -- failed to compile a file into an Abstract Syntax Tree

[SylvainCorlay]

Thanks @cclauss!