Help with script to copy from doctype to another

I am using this script:

frappe.ui.form.on('Planeacion Didactica', {

    //The trigger can be changed, but refresh must be used to use a button

    refresh: function(frm) {

        //The following line creates a button.


            //The function below is triggered when the button is pressed.

            function() {


                    "method": "frappe.client.set_value",

                    "args": {

                        //replace "Target DocType" with the actual target doctype

                        "doctype": "Grupo Estudiantes",

                        //replace target_doctype_link with a link to the document to be changed

                        "name": frm.doc.grupo_estudiantes,

                        "fieldname": {

                            //You can update as many fields as you want.  

                            "seccion": frm.doc.grupo,

                            "porcentaje_parcial_1": frm.doc.unidad  //Make sure that you do not put a comma over the last value







But when I clicked on button I received this error: