check for PEP 8 naming conventions (flake8 plugin for Python3)

 The PEP 8 recommendation is a style guide for Python code. This plugin for
 flake8 checks whether the naming conventions of PEP 8 have been complied
 with. However written as plugin for flake8, some tools make independent use
 of the module.
 .
 This package contains the module for Python3.