code: func (e Event) Id() common.Hash {
  	types := make([]string, len(e.Inputs))
  	i := 0
  	for _, input := range e.Inputs {
  		types[i] = input.Type.String()
  		i++
  	}
  	return common.BytesToHash(crypto.Keccak256([]byte(fmt.Sprintf("%v(%v)", e.Name, strings.Join(types, ",")))))
  }
docs: // Id returns the canonical representation of the event's signature used by the
  // abi definition to identify event names and types.