I'm new to JS coding for Odoo. I'm getting this error message and I can't figure out what I've done wrong. Code is below. Don't know why my instance is undefined. Any ideas?

Error:

Uncaught TypeError: Cannot read property 'include' of undefined

Code:

openerp.context_views = function(instance){

instance.web.ViewManager.include({

switch_mode: function(){

var self = this;

var model = new instance.web.Model("context_views.context_views");

model.call("_get_context", {context: new instance.web.CompoundContext({'view_type': this.view_type})});

this._super();

},

});

};