Bitwise left shift

def shl(computation: BaseComputation) -> None:
    """
    Bitwise left shift
    """
    shift_length, value = computation.stack_pop(num_items=2, type_hint=constants.UINT256)

    if shift_length >= 256:
        result = 0
    else:
        result = (value << shift_length) & constants.UINT_256_MAX

    computation.stack_push(result)