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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 add_query(self, query, join_with=AND):
 """Join a new query to existing queries on the stack. Args: query (tuple or list or DomainCondition):
 The condition for the query. If a ``DomainCondition`` object is not provided, the input should conform to the interface defined in :func:`~.domain.DomainCondition.from_tuple`. join_with (str):
 The join string to apply, if other queries are already on the stack. """

        if not isinstance(query, DomainCondition):
            query = DomainCondition.from_tuple(query)
        if len(self.query):
            self.query.append(join_with)
        self.query.append(query)