code: def skip_regex(lines_enum, options):
      # type: (ReqFileLines, Optional[optparse.Values]) -> ReqFileLines
      
      skip_regex = options.skip_requirements_regex if options else None
      if skip_regex:
          pattern = re.compile(skip_regex)
          lines_enum = filterfalse(lambda e: pattern.search(e[1]), lines_enum)
      return lines_enum
docs: Skip lines that match '--skip-requirements-regex' pattern
  
      Note: the regex pattern is only built once