# Python < 3.2
def raise_from(value, from_value):
    raise value
# Python == 3.2
def raise_from(value, from_value):
    try:
        if from_value is None:
            raise value
        raise value from from_value
    finally:
        value = None
# Python > 3.2
def raise_from(value, from_value):
    try:
        raise value from from_value
    finally:
        value = None