func RemoveHelper(name string) {
	helpersMutex.Lock()
	defer helpersMutex.Unlock()
	delete(helpers, name)
}
RemoveHelper unregisters a global helper
package raymond
import (
	"fmt"
	"log"
	"reflect"
	"sync"
)
type Options struct {
	eval *evalVisitor
	params []interface{}
	hash   map[string]interface{}
}
var helpers = make(map[string]reflect.Value)
var helpersMutex sync.RWMutex
func init() {
	RegisterHelper("if", ifHelper)
	RegisterHelper("unless", unlessHelper)
	RegisterHelper("with", withHelper)
	RegisterHelper("each", eachHelper)
	RegisterHelper("log", logHelper)
	RegisterHelper("lookup", lookupHelper)
	RegisterHelper("equal", equalHelper)
}
func RegisterHelper(name string, helper interface{}) {
	helpersMutex.Lock()
	defer helpersMutex.Unlock()
	if helpers[name] != zero {
		panic(fmt.Errorf("Helper already registered: %s", name))
	}
	val := reflect.ValueOf(helper)
	ensureValidHelper(name, val)
	helpers[name] = val
}
func RegisterHelpers(helpers map[string]interface{}) {
	for name, helper := range helpers {
		RegisterHelper(name, helper)
	}
}