code: def get_session(username, password, cookie_path=COOKIE_PATH, cache=True,
                  cache_expiry=300, cache_path=CACHE_PATH, driver='phantomjs'):
      
      class USPSAuth(AuthBase):  # pylint: disable=too-few-public-methods
          """USPS authorization storage."""
  
          def __init__(self, username, password, cookie_path, driver):
              """Init."""
              self.username = username
              self.password = password
              self.cookie_path = cookie_path
              self.driver = driver
  
          def __call__(self, r):
              """Call is no-op."""
              return r
  
      session = requests.Session()
      if cache:
          session = requests_cache.core.CachedSession(cache_name=cache_path,
                                                      expire_after=cache_expiry)
      session.auth = USPSAuth(username, password, cookie_path, driver)
      session.headers.update({'User-Agent': USER_AGENT})
      if os.path.exists(cookie_path):
          _LOGGER.debug("cookie found at: %s", cookie_path)
          session.cookies = _load_cookies(cookie_path)
      else:
          _login(session)
      return session
docs: Get session, existing or new.