Most of the time we try to provide string but it will be byte32 in following format. // 'ETH' as a bytes32 string '0x4554480000000000000000000000000000000000000000000000000000000000'

Do not forget to remove single cote at the time of input.

Most of the time we try to provide a string but it has to be bytes32 in the following format:

// 'ETH' as a bytes32 string 0x4554480000000000000000000000000000000000000000000000000000000000