In lpython v18.1, the class UnsignedInteger, defined in lpython.py doesn't support bitwise shift operators. Please add something like: ``` def __lshift__(self, other): if isinstance(other, self.__class__): return UnsignedInteger(self.bit_width, self.value << other.value) else: raise TypeError("Unsupported operand type") def __rshift__(self, other): if isinstance(other, self.__class__): return UnsignedInteger(self.bit_width, self.value >> other.value) else: raise TypeError("Unsupported operand type") ```