code: def get_service_regex(base_url, service_url, sub_service):
          
          # if the specified service_url is already a regex
          # then just use. Otherwise create what we need
          if StackInABoxService.is_regex(service_url):
              logger.debug('StackInABoxService: Received regex {0} for use...'
                           .format(service_url.pattern))
  
              # Validate the regex against StackInABoxService requirement
              StackInABoxService.validate_regex(service_url, sub_service)
  
              return service_url
          else:
              regex = '^{0}{1}$'.format('', service_url)
              logger.debug('StackInABoxService: {0} + {1} -> {2}'
                           .format(base_url, service_url, regex))
              return re.compile(regex)
docs: Get the regex for a given service.
  
          :param base_url: string - Base URI
          :param service_url: string - Service URI under the Base URI
          :param sub_service: boolean - is the Service URI for a sub-service?
  
          :returns: Python Regex object containing the regex for the Service