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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 transform_string(self, jsx, harmony=False, strip_types=False):
 """ Transform ``jsx`` JSX string into javascript :param jsx: JSX source code :type jsx: basestring :keyword harmony: Transform ES6 code into ES3 (default: False) :type harmony: bool :keyword strip_types: Strip type declarations (default: False) :type harmony: bool :return: compiled JS code :rtype: str """

        opts = {'harmony': harmony, 'stripTypes': strip_types}
        try:
            result = self.context.call(
                '%s.transform' % self.JSX_TRANSFORMER_JS_EXPR, jsx, opts)
        except execjs.ProgramError as e:
            raise TransformError(str(e))
        js = result['code']
        return js