setMerchantChannel method
Set merchant channel
length of value
is 3.
Implementation
setMerchantChannel(String value) {
if (value.length != 3) {
throw ValueLengthErr(title: "MerchantChannel", length: "3");
}
final merchantChannel = setTLV(value, AdditionalID.merchantChannel);
this.value = this.value.copyWith(merchantChannel: merchantChannel);
}