'Parameters
contrast_L : True or False
Whether to show contrast_L matrix
transform_M : True or False
Whether to show transform_M matrix'

def summary(self, show_contrast_L=False, show_transform_M=False, show_constant_C=False):

    summ = summary2.Summary()
    summ.add_title('Multivariate    linear    model')
    for key in self.results:
        summ.add_dict({'': ''})
        df = self.results[key]['stat'].copy()
        df = df.reset_index()
        c = df.columns.values
        c[0] = key
        df.columns = c
        df.index = ['', '', '', '']
        summ.add_df(df)
        if show_contrast_L:
            summ.add_dict({key: '    contrast    L='})
            df = pd.DataFrame(self.results[key]['contrast_L'], columns=self.exog_names)
            summ.add_df(df)
        if show_transform_M:
            summ.add_dict({key: '    transform    M='})
            df = pd.DataFrame(self.results[key]['transform_M'], index=self.endog_names)
            summ.add_df(df)
        if show_constant_C:
            summ.add_dict({key: '    constant    C='})
            df = pd.DataFrame(self.results[key]['constant_C'])
            summ.add_df(df)
    return summ
