code: protected void handleError(SPFError err) {
  		if (err.codeEquals(SPFError.TOKEN_NOT_VALID_ERROR_CODE)) {
  			AccessTokenManager.get(mContext).invalidateToken();
  		}
  		mCallback.onError(err);
  	}
docs: Performs common error handling operations. Subclasses may override it to
  provide specific behavior.
  
  @param err