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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 getValue(self, scalarExpression):
 """ Get a scalar value from the underlying AMPL interpreter, as a double or a string. Args: scalarExpression: An AMPL expression which evaluates to a scalar value. Returns: The value of the expression. """

        return lock_and_call(
            lambda: Utils.castVariant(self._impl.getValue(scalarExpression)),
            self._lock
        )