def test_ignoresLeadingWhitespaceAndEmptyLines(self):
        """
        L{checkers.readAuthorizedKeyFile} ignores leading whitespace in
        lines, as well as empty lines
        """
        fileobj = BytesIO(b"""
                           # ignore
                           not ignored
                           """)
        result = checkers.readAuthorizedKeyFile(fileobj, parseKey=lambda x: x)
        self.assertEqual([b'not ignored'], list(result))

        L{checkers.readAuthorizedKeyFile} ignores leading whitespace in
        lines, as well as empty lines
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_checkers.py