func (c *StandardClaims) Valid() error {
	if err := c.StandardClaims.Valid(); err != nil {
		return err
	}

	if c.AccessKey == "" && c.Subject == "" {
		return jwtgo.NewValidationError("accessKey/sub missing",
			jwtgo.ValidationErrorClaimsInvalid)
	}

	return nil
}

// NewMapClaims - Initializes a new map claims
func NewMapClaims() *MapClaims {
	return &MapClaims{MapClaims: jwtgo.MapClaims{}}
}

	String  *LiteralString `parser:" | @LitString"`
	Boolean *Boolean       `parser:" | @(\"TRUE\" | \"FALSE\")"`
	Null    bool           `parser:" | @\"NULL\""`
	Missing bool           `parser:" | @\"MISSING\")"`
}

// Identifier represents a parsed identifier
type Identifier struct {
	Unquoted *string           `parser:"  @Ident"`
	Quoted   *QuotedIdentifier `parser:"| @QuotIdent"`
}