code: def regex(regex):
      
      if not hasattr(regex, 'pattern'):
          regex = re.compile(regex)
  
      pattern = regex.pattern
      flags = regex.flags
  
      codes = sre.parse(pattern)
  
      return _strategy(codes, Context(flags=flags)).filter(regex.match)
docs: Return strategy that generates strings that match given regex.
  
      Regex can be either a string or compiled regex (through `re.compile()`).
  
      You can use regex flags (such as `re.IGNORECASE`, `re.DOTALL` or `re.UNICODE`)
      to control generation. Flags can be passed either in compiled regex (specify
      flags in call to `re.compile()`) or inside pattern with (?iLmsux) group.
  
      Some tricky regular expressions are partly supported or not supported at all.
      "^" and "$" do not affect generation. Positive lookahead/lookbehind groups
      are considered normal groups. Negative lookahead/lookbehind groups do not do
      anything. Ternary regex groups ('(?(name)yes-pattern|no-pattern)') are not
      supported at all.