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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 noise_gaussian(self, mean, std):
 """Create a gaussian noise variable"""

        assert std > 0
        ng = self.sym.sym('ng_{:d}'.format(len(self.scope['ng'])))
        self.scope['ng'].append(ng)
        return mean + std*ng