(self, formula)
return self.create_node(node_type=op.NOT, args=(formula,))
Creates an expression of the form:
            not formula

        Restriction: Formula must be of boolean type
Creates an expression of the form:
            not formula
Creates an expression of the form : not formula
def Not(self, formula):
        """ Creates an expression of the form:
            not formula

        Restriction: Formula must be of boolean type
        """
        if formula.is_not():
            return formula.arg(0)
        return self.create_node(node_type=op.NOT, args=(formula,))
def Not ( self , formula ) : if formula . is_not ( ) : return formula . arg ( 0 ) return self . create_node ( node_type = op . NOT , args = ( formula , ) )