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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 compile(self, expr, params=None, limit=None):
 """ Translate expression to one or more queries according to backend target Returns ------- output : single query or list of queries """

        query_ast = self._build_ast_ensure_limit(expr, limit, params=params)
        return query_ast.compile()