def coupon_identify_customer(customer, address, document):
    """ Identify the customer.  This method doesn't have mandatory
        execution (you can identify the customer only if you like), but when
        executed it must be called before calling any method.

        @param customer:
        @type customer:   str

        @param address:
        @type address:    str

        @param document:
        @type document:   str
        """
