code: func bindTopicTypeGo(kind abi.Type) string {
  	bound := bindTypeGo(kind)
  	if bound == "string" || bound == "[]byte" {
  		bound = "common.Hash"
  	}
  	return bound
  }
docs: // bindTypeGo converts a Solidity topic type to a Go one. It is almost the same
  // funcionality as for simple types, but dynamic types get converted to hashes.