* correct docstring
* add type annotation to trade_count_lock
* fix indentations
* allow globals in hyperopt.py
* fix import order
* simplify asserts
* use proper variable name
* simplify condition
* fix path operation that fails on windows
* autopep fixes
* remove unused imports
* fix plot_dataframe.py lint warnings
* make pep8 error fails the build
* two more line breakings
* matplotlib.use() must be called before pyplot import
