code: func (c *nativeStore) getCredentialsFromStore(serverAddress string) (types.AuthConfig, error) {
  	var ret types.AuthConfig
  
  	creds, err := client.Get(c.programFunc, serverAddress)
  	if err != nil {
  		if credentials.IsErrCredentialsNotFound(err) {
  			// do not return an error if the credentials are not
  			// in the keychain. Let docker ask for new credentials.
  			return ret, nil
  		}
  		return ret, err
  	}
  
  	if creds.Username == tokenUsername {
  		ret.IdentityToken = creds.Secret
  	} else {
  		ret.Password = creds.Secret
  		ret.Username = creds.Username
  	}
  
  	ret.ServerAddress = serverAddress
  	return ret, nil
  }
docs: // getCredentialsFromStore executes the command to get the credentials from the native store.