code: def assert_conditions(self):
          
          self.assert_condition_md5()
          etag = self.clean_etag(self.call_method('get_etag'))
          self.response.last_modified = self.call_method('get_last_modified')
          self.assert_condition_etag()
          self.assert_condition_last_modified()
docs: Handles various HTTP conditions and raises HTTP exceptions to
          abort the request.
  
              - Content-MD5 request header must match the MD5 hash of the full
                input (:func:`assert_condition_md5`).
              - If-Match and If-None-Match etags are checked against the ETag of
                this resource (:func:`assert_condition_etag`).
              - If-Modified-Since and If-Unmodified-Since are checked against
                the modification date of this resource
                (:func:`assert_condition_last_modified`).
  
          .. todo:: Return a 501 exception when any Content-* headers have been
                    set in the request. (See :rfc:`2616`, section 9.6)