Undefined name 'download_async'

[cclauss]

flake8 testing of https://github.com/notadamking/RLTrader on Python 3.7.1

$ flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics

./lib/cli/functions/update_data.py:42:5: F821 undefined name 'download_async'
    download_async()
    ^
1     F821 undefined name 'download_async'
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