value is a valid HexString | HexString.
If length is true or a number, it also checks that value is a valid DataHexString | DataHexString of
length (if a number) bytes of data (e.g. 0x1234 is 2 bytes).
value is a valid HexString | HexString.
If length is true or a number, it also checks that value is a valid DataHexString | DataHexString of
length (if a number) bytes of data (e.g. 0x1234 is 2 bytes).