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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _sign_of(money):
 """Determines the amount sign of a money instance Args: money (:class:`endpoints_management.gen.servicecontrol_v1_messages.Money`):
 the instance to test Return: int: 1, 0 or -1 """

    units = money.units
    nanos = money.nanos
    if units:
        if units > 0:
            return 1
        elif units < 0:
            return -1
    if nanos:
        if nanos > 0:
            return 1
        elif nanos < 0:
            return -1
    return 0