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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 _body_builder(self, kwargs):
 """ Helper method to construct the appropriate SOAP-body to call a FritzBox-Service. """

        p = {
            'action_name': self.name,
            'service_type': self.service_type,
            'arguments': '',
            }
        if kwargs:
            arguments = [
                self.argument_template % {'name': k, 'value': v}
                for k, v in kwargs.items()
            ]
            p['arguments'] = ''.join(arguments)
        body = self.body_template.strip() % p
        return body