def __init__(self, guid, words, labels, langs=None):
        """Constructs a InputExample.

        Args:
          guid: Unique id for the example.
          words: list. The words of the sequence.
          labels: (Optional) list. The labels for each word of the sequence. This should be
          specified for train and dev examples, but not for test examples.
        """
        self.guid = guid
        self.words = words
        self.labels = labels
        self.langs = langs
Constructs a InputExample.

        Args:
          guid: Unique id for the example.
          words: list. The words of the sequence.
          labels: (Optional) list. The labels for each word of the sequence. This should be
          specified for train and dev examples, but not for test examples.
        
xtune/src/utils_tag.py