<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def deviance(self, endog, mu, freq_weights=1., scale=1.):
 """ Gaussian deviance function Parameters endog : array-like Endogenous response variable mu : array-like Fitted mean response variable freq_weights : array-like 1d array of frequency weights. The default is 1. scale : float, optional An optional scale argument. The default is 1. Returns ------- deviance : float The deviance function at (endog,mu,freq_weights,scale) as defined below. """

        return np.sum((freq_weights * (endog - mu)**2)) / scale