def __str__(self):
        """
        String representation of list of termnames of a formula.
        """
        value = []
        for term in self.terms:
            value += [term.termname]
        return '<formula: %s>' % ' + '.join(value)
dataset/ETHPy150Open statsmodels/statsmodels/statsmodels/sandbox/formula.py/Formula.__str__/original