A unique value identifying this subscription.

This is an optional header. Providing this header will allow you to receive localized result of this API. The system will fetch available template translations from localization service under your account and will provide translated rendered template. Accepted values: AF, AR, AR-DZ, AST, AZ, BE, BG, BN, BR, BS, CA, CKB, CS, CY, DA, DE, DSB, EL, EN, EN-AU, EN-GB, EO, ES, ES-AR, ES-CO, ES-MX, ES-NI, ES-VE, ET, EU, FA, FI, FR, FY, GA, GD, GL, HE, HI, HR, HSB, HU, HY, IA, ID, IG, IO, IS, IT, JA, KA, KAB, KK, KM, KN, KO, KY, LB, LT, LV, MK, ML, MN, MR, MS, MY, NB, NE, NL, NN, NO, OS, PA, PL, PT, PT-BR, RO, RU, SK, SL, SQ, SR, SR-LATN, SV, SW, TA, TE, TG, TH, TK, TR, TT, UDM, UK, UR, UZ, VI, ZH-CN, ZH-HANS, ZH-HANT, ZH-HK, ZH-MO, ZH-MY, ZH-SG, ZH-TW. As an alternative, you can also provide in this header the exact translation id you would like to use, i.e. TRN-1234-5678-9101. Such translation must exist under your account in localization service, it may or may not be active.