Google Apps Script - MailApp doesn't work with my script

Question

Sorry for the sloppy code. I'm brand new to this. I'm trying to make it so that upon hitting Browser.Buttons.YES_NO , when yes is selected it executes the code and sends an email with a predetermined message. Whenever I try to put in MailApp.sendEmail("email@gmail.com", "test", "test"); in it breaks the code, causing it to not execute. Any help would be appreciated.

function onEdit(event) {
    var ss = SpreadsheetApp.getActiveSpreadsheet();
    var s = event.source.getActiveSheet();
    var r = event.source.getActiveRange();

    if(s.getName() == "to do" && r.getColumn() == 13 && r.getValue() == "yes") {  
      var confirm = Browser.msgBox("Mark this job as complete?", Browser.Buttons.YES_NO);

      if(confirm == "yes") { //I would like to put the MailApp inside this if statement 
        var row = r.getRow();
        var numColumns = s.getLastColumn();
        var targetSheet = ss.getSheetByName("done");
        var target = targetSheet.getRange(targetSheet.getLastRow() + 1, 1);
        s.getRange(row, 1, 1, numColumns).moveTo(target);
        s.deleteRow(row);
        return Browser.msgBox("File transferred", Browser.Buttons.OK); 
      }
   }
}

Answer 1

function onEdit(event) {
    var ss = SpreadsheetApp.getActiveSpreadsheet();
    var s = event.source.getActiveSheet();
    var r = event.source.getActiveRange();

    if(s.getName() == "to do" && r.getColumn() == 13 && r.getValue() == "yes") {  
      var confirm = Browser.msgBox("Mark this job as complete?", Browser.Buttons.YES_NO);

      if(confirm == "yes") { //I would like to put the MailApp inside this if statement 
        var row = r.getRow();
        var numColumns = s.getLastColumn();
        var targetSheet = ss.getSheetByName("done");
        var target = targetSheet.getRange(targetSheet.getLastRow() + 1, 1);
        s.getRange(row, 1, 1, numColumns).moveTo(target);
        s.deleteRow(row);
        return Browser.msgBox("File transferred", Browser.Buttons.OK); 
      }
   }
}

You missed the opening curly bracket