'return tables as string
Returns
latex : string
summary tables and extra text as string of Latex
Notes
This currently merges tables with different number of columns.
It is recommended to use `as_latex_tabular` directly on the individual
tables.'

def as_latex(self):

    latex = summary_return(self.tables, return_fmt='latex')
    if (not (self.extra_txt is None)):
        latex = ((latex + '\n\n') + self.extra_txt.replace('\n', '    \\newline\n    '))
    return latex
