def when(self, *bools):
        """
        :type bools: bool
        :param bools: Boolean arguments

        All boolean arguments passed to this method must evaluate to `True` for
        printing to be enabled.

        So for example, the following code would print ``x: 1``

        .. code-block:: python

           for x in range(10):
               Behold().when(x == 1).show('x')
        """
        self.passes = self.passes and all(bools)
        return self