docs: def retrieve_api_token(self):
          """
          Retrieve the access token from AVS.
  
          This function is memoized, so the
          value returned by the function will be remembered and returned by
          subsequent calls until the memo expires. This is because the access
          token lasts for one hour, then a new token needs to be requested.
  
          Decorators:
              helpers.expiring_memo
  
          Returns:
              str -- The access token for communicating with AVS
  
          """
  
          payload = self.oauth2_manager.get_access_token_params(
              refresh_token=self.refresh_token
          )
          response = requests.post(
              self.oauth2_manager.access_token_url, json=payload
          )
          response.raise_for_status()
          response_json = json.loads(response.text)
          return response_json['access_token']