def _raise_if_null(self, other):
        """
        :raises ValueError: if either self or other is a null Interval
        """
        if self.is_null():
            raise ValueError("Cannot compare null Intervals!")
        if hasattr(other, 'is_null') and other.is_null():
            raise ValueError("Cannot compare null Intervals!")
def _raise_if_null ( self , other ) : if self . is_null ( ) : raise ValueError ( "Cannot compare null Intervals!" ) if hasattr ( other , 'is_null' ) and other . is_null ( ) : raise ValueError ( "Cannot compare null Intervals!" )
:raises ValueError: if either self or other is a null Interval