         repository.configuration.extendBaseContext(Box(["foo": "bar"]))
         
         // "bar"
-        let template2 = repository.template(string: "{{foo}}")!
-        template2.render()!
+        let template2 = try! repository.template(string: "{{foo}}")
+        try! template2.render()
     
     The base context can also be extended for individual templates:
 
-        let template3 = Template(string: "{{foo}}")!
+        let template3 = try! Template(string: "{{foo}}")
         template3.extendBaseContext(Box(["foo": "bar"]))
         
         // "bar"
-        template3.render()!
+        try! template3.render()
 
     - parameter box: The box pushed on the top of the context stack
     

        // Globally, with Mustache.DefaultConfiguration:
    
        Mustache.DefaultConfiguration.tagDelimiterPair = ("<%", "%>")
        let template1 = Template(string: "<% name %>)!
    
        // Locally, using a TemplateRepository:
    
        let repository = TemplateRepository(bundle: NSBundle.mainBundle())
        repository.configuration.tagDelimiterPair = ("[[", "]]")
        let HTMLTemplate = repository.template(string: "[[ name ]]")!
    
    You can also change the delimiters right in your templates using a "Set
    Delimiter tag": `{{=[[ ]]=}}` changes delimiters to `[[` and `]]`.

        repository.configuration.registerInBaseContext("foo", Box("bar"))
        
        // "bar"
        let template2 = try! repository.template(string: "{{foo}}")
        try! template2.render()
    
    Keys can also be registered in the base context of individual templates:

        let template3 = try! Template(string: "{{foo}}")
        template3.registerInBaseContext("foo", Box("bar"))
        
        // "bar"
        try! template3.render()

    
    - parameter key: An identifier
