code: func ValidMsg(schema json.RawMessage, msg Message) bool {
  	sch := gojsonschema.NewBytesLoader(schema)
  	loader := gojsonschema.NewGoLoader(msg)
  
  	result, err := gojsonschema.Validate(sch, loader)
  	if err != nil || !result.Valid() || len(result.Errors()) != 0 {
  		return false
  	}
  	return true
  }
docs: // ValidMsg if is true then offering message corresponds
  // to an offer template scheme.