Fix linting

Author: nicoddemus

testing/test_warnings.py

@@ -151,7 +151,6 @@ def test_func(fix):
     )
 
 
-
 def test_works_with_filterwarnings(testdir):
     """Ensure our warnings capture does not mess with pre-installed filters (#2430)."""
     testdir.makepyfile(
@@ -502,7 +501,6 @@ def test_hidden_by_system(self, testdir, monkeypatch):
         assert WARNINGS_SUMMARY_HEADER not in result.stdout.str()
 
 
-
 @pytest.mark.parametrize("change_default", [None, "ini", "cmdline"])
 def test_removed_in_pytest4_warning_as_error(testdir, change_default):
     testdir.makepyfile(