func (c Claims) Del(key string) {
	delete(c, key)
}
Del removes the value that corresponds with key from the Claims.
package jwt
import (
	"encoding/json"
	"time"
	"github.com/SermoDigital/jose"
)
type Claims map[string]interface{}
func (c Claims) Validate(now time.Time, expLeeway, nbfLeeway time.Duration) error {
	if exp, ok := c.Expiration(); ok {
		if now.After(exp.Add(expLeeway)) {
			return ErrTokenIsExpired
		}
	}
	if nbf, ok := c.NotBefore(); ok {
		if !now.After(nbf.Add(-nbfLeeway)) {
			return ErrTokenNotYetValid
		}
	}
	return nil
}
func (c Claims) Get(key string) interface{} {
	if c == nil {
		return nil
	}
	return c[key]
}
func (c Claims) Set(key string, val interface{}) {
	c[key] = val
}