Need a way to ignore docstrings for "private" methods

Need an option to avoid documenting, `"def _private_method(param1, param2)"`;

Currently it gives, `DCO010 docstring should be defined for a function/ method/ class, more information: https://github.com/jdkandersson/flake8-docstrings-complete#fix-dco010`