(self, formula)
return not self.is_sat(Not(formula))
Checks validity of the formula w.r.t. the current state of the
        solver.

        Previous assertions are taken into account. See :py:func:`is_sat`

        :type formula: FNode
        :returns: Whether formula is valid
        :rtype: bool
Checks validity of the formula w.r.t. the current state of the
        solver.
Checks validity of the formula w . r . t . the current state of the solver .
def is_valid(self, formula):
        """Checks validity of the formula w.r.t. the current state of the
        solver.

        Previous assertions are taken into account. See :py:func:`is_sat`

        :type formula: FNode
        :returns: Whether formula is valid
        :rtype: bool
        """
        Not = self.environment.formula_manager.Not
        return not self.is_sat(Not(formula))
def is_valid ( self , formula ) : Not = self . environment . formula_manager . Not return not self . is_sat ( Not ( formula ) )