If you use Python virtualenv, pylint and lxml together, you may see error messages in pylint test results. It`s because only trusted C extension resources (the standard library) should be used. Here is an opportunity to improve the pylint test results.
Generate a .pylintrc file
# generate .pylintrc file
$ pylint --generate-rcfile > .pylintrc
Open the .pylintrc file to edit
# open with vim editor
$ vim .pylintrc
Add lxml to extension-pkg-whitelist
# A comma-separated list of package or module names from where C extensions may
# be loaded. Extensions are loading into the active Python interpreter and may
# run arbitrary code
extension-pkg-whitelist=lxml
If you now perform the pylint test again, no error relating to lxml should appear.