I. Introduction
Sentiment analysis is a computational study of people’s opinions, attitudes, and emotions toward an entity, which can be an individual, an event, or a topic [1]. Sentiment analysis for software engineering (SA4SE) has drawn much attention in recent years [2]–[10]. Most research considers sentiment analysis as a sentiment polarity classification task. For a given text unit, the goal is to determine its sentiment orientation, i.e., negative, neutral, or positive.