根据已有数据集训练一个文本分类器，用于对新数据进行分类。


已有数据集包括5000个针对电影评论的数据，分为正面和负面两类，具体格式为：
- 正面评论：The acting was superb and the plot kept me engaged throughout the entire film.
- 负面评论：The movie was a total disaster. The acting was terrible and the plot was confusing.
You can train a text classifier using the existing dataset of 5000 movie reviews, with positive and negative categories. The model can be used to classify new data based on the text input.