code: public void setAccessToken(String accessToken, String tokenType) throws HelloSignException {
          auth.setAccessToken(accessToken, tokenType);
      }
docs: Sets the access token for the OAuth user that this client will use to
  perform requests.
  
  @param accessToken String access token
  @param tokenType String token type
  @throws HelloSignException thrown if there's a problem setting the access
  token.