validate signature error Signature count is 2 more than key counts of permission : 1

[anikeeva91]

When I set the owner permission to two addresses and use both addresses' private keys to double sign, I can broadcast transactions normally

But when I set the active address to two addresses and double sign with both addresses, the error message 'validate signature error Signature count is 2 more than key counts of permission: 1'

I use this code like

rawData, _ := proto.Marshal(tx.GetRawData())
h256h := sha256.New()
h256h.Write(rawData)
hash := h256h.Sum(nil)
signature1, err := crypto.Sign(hash, privateKey1)
signature2, err := crypto.Sign(hash, privateKey2)
signature3, err := crypto.Sign(hash, privateKey3)
tx.Signature = append(tx.Signature, signature1)
tx.Signature = append(tx.Signature, signature2)
tx.Signature = append(tx.Signature, signature3)
result, err := c.Broadcast(tx)