code: def unescape(escaped, escape_char=ESCAPE_CHAR):
      
      if isinstance(escaped, bytes):
          # always work on text
          escaped = escaped.decode('utf8')
      
      escape_pat = re.compile(re.escape(escape_char).encode('utf8') + b'([a-z0-9]{2})', re.IGNORECASE)
      buf = escape_pat.subn(_unescape_char, escaped.encode('utf8'))[0]
      return buf.decode('utf8')
docs: Unescape a string escaped with `escape`
      
      escape_char must be the same as that used in the call to escape.