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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 provideCustomerReferralCode(sender,**kwargs):
    '''
    If the vouchers app is installed and referrals are enabled, then the customer's profile page can show their voucher referral code.
    '''
    customer = kwargs.pop('customer')
    if getConstant('vouchers__enableVouchers') and getConstant('referrals__enableReferralProgram'):
        vrd = ensureReferralVouchersExist(customer)

        return {
            'referralVoucherId': vrd.referreeVoucher.voucherId
        }