code: func (ma *MixedcaseAddress) UnmarshalJSON(input []byte) error {
  	if err := hexutil.UnmarshalFixedJSON(addressT, input, ma.addr[:]); err != nil {
  		return err
  	}
  	return json.Unmarshal(input, &ma.original)
  }
docs: // UnmarshalJSON parses MixedcaseAddress