def __enter__(self):
        """Raises the second need's error if neither are met. Raises the first
            need's error if both are met.
        """
        f = bool(self.first_need)
        s = bool(self.second_need)

        if not f and not s:
            with self.second_need:
                pass
        elif f and s:
            with ~self.first_need:
                pass
def __enter__ ( self ) : f = bool ( self . first_need ) s = bool ( self . second_need ) if not f and not s : with self . second_need : pass elif f and s : with ~ self . first_need : pass
Raises the second need's error if neither are met. Raises the first
            need's error if both are met.