def METHOD_NAME(self, params):
    """
    Construct results
    params : ndarray
        Model parameters
    Notes
    -----
    Allows results to be constructed from either existing parameters or
    when estimated using using ``fit``
    """
    fitted_values = self.exog.dot(params)
    resid = self.endog - fitted_values
    wresid = self.wendog - self.wexog.dot(params)
    df_resid = self.wexog.shape[0] - self.wexog.shape[1]
    scale = np.dot(wresid, wresid) / df_resid
    return Bunch(params=params, fittedvalues=fitted_values, resid=resid,
                 model=self, scale=scale)