title: Detect latin characters in regex
body: <p>I want to apply a regex on a Latin text, and I followed the solution in this question: <a href="https://stackoverflow.com/questions/18663644/how-to-account-for-accent-characters-for-regex-in-python">How to account for accent characters for regex in Python?</a>, where they suggest to add a # character before the regex.</p>
  
  <pre><code>def clean_str(string):
      string = re.sub(r"#(@[a-zA-Z_0-9]+)", " ", string, re.UNICODE)
      string = re.sub(r'#([^a-zA-Z0-9#])', r' \1 ', string, re.UNICODE)
      string = re.sub(r'#([^a-zA-Z0-9#])', r' ', string, re.UNICODE)
      string = re.sub(r'(\s{2,})', ' ', string, re.UNICODE)
      return string.lower().strip()
  </code></pre>
  
  <p>My problem is, the regex work in detecting the latin characters, but nothing is applied from the regex set on the text.</p>
  
  <p>example:
  if I have a text like "@aaa bbb các. ddd".</p>
  
  <p>it should be like "bbb các . ddd" with space "before the DOT" and with deleting the Tag "@aaa".</p>
  
  <p>But it produces the same input text!: "@aaa bbb các. ddd"</p>
  
  <p>Did I miss something?</p>