signature/policy_config.go
func (kt *sbKeyType) UnmarshalJSON(data []byte) error {
	*kt = sbKeyType("")
	var s string
	if err := json.Unmarshal(data, &s); err != nil {
		return err
	}
	if !sbKeyType(s).IsValid() {
		return InvalidPolicyFormatError(fmt.Sprintf("Unrecognized keyType value \"%s\"", s))
	}
	*kt = sbKeyType(s)
	return nil
}
func (kt *sbKeyType) UnmarshalJSON(data []byte) error {
	*kt = sbKeyType("")
	var s string
	if err := json.Unmarshal(data, &s); err != nil {
		return err
	}
	if !sbKeyType(s).IsValid() {
		return InvalidPolicyFormatError(fmt.Sprintf("Unrecognized keyType value \"%s\"", s))
	}
	*kt = sbKeyType(s)
	return nil
}
// UnmarshalJSON implements the json.Unmarshaler interface.