code: func soapFault(err error) (*soap.Fault, bool) {
  	if soap.IsSoapFault(err) {
  		return soap.ToSoapFault(err), true
  	}
  	return nil, false
  }
docs: // soapFault extracts the SOAP fault from an error fault, if it exists. Check
  // the returned boolean value to see if you have a SoapFault.