code: def validate_query(query):
          
          tokens = _quote_re.findall(query)
          for token in tokens:
              if token.startswith('"') and token.endswith('"'):
                  continue
              if set(token) & _invalid_ascii:
                  return False
          return True
docs: Simple helper function to indicate whether a search query is a
          valid FTS5 query. Note: this simply looks at the characters being
          used, and is not guaranteed to catch all problematic queries.