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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _and_join(self, terms):
 """ Joins terms using AND operator. Args: terms (list):
 terms to join Examples: self._and_join(['term1']) -> 'term1' self._and_join(['term1', 'term2']) -> 'term1 AND term2' self._and_join(['term1', 'term2', 'term3']) -> 'term1 AND term2 AND term3' Returns: str """

        if len(terms) > 1:
            return ' AND '.join([self._or_join(t) for t in terms])
        else:
            return self._or_join(terms[0])