<li><strong>By default, decimal characters, alphanumerics and whitespaces from all alphabets are matched unless <codeclass="python hljs"><spanclass="hljs-string">'flags=re.ASCII'</span></code> argument is used.</strong></li>
<li><strong>As shown below, it restricts special sequence matches to the first 128 characters and prevents <codeclass="python hljs"><spanclass="hljs-string">'\s'</span></code> from accepting <codeclass="python hljs"><spanclass="hljs-string">'[\x1c\x1d\x1e\x1f]'</span></code>.</strong></li>
<li><strong>As shown below, it restricts special sequence matches to the first 128 characters and prevents <codeclass="python hljs"><spanclass="hljs-string">'\s'</span></code> from accepting <codeclass="python hljs"><spanclass="hljs-string">'[\x1c-\x1f]'</span></code>.</strong></li>
<li><strong>Use a capital letter for negation.</strong></li>