how to remove header row from UISearchController's search results

I have a tableViewController, MainData.swift, where I add a searchbar programmatically in it's viewDidLoad

 var searchController:UISearchController!
 let resultsController = SearchResultsController()

    override func viewDidLoad() {
        super.viewDidLoad()

        searchController = UISearchController(searchResultsController: resultsController)

        let searchBar = searchController.searchBar
        searchBar.placeholder = "Search for a student"
        searchBar.sizeToFit()
        tableView.tableHeaderView = searchBar

        searchController.searchResultsUpdater = resultsController
    }

I then created my own class to handle the search, SearchResultsController.swift. Searching works fine but I cannot remove the header as shown here. I've tried setting the tableheaderview to nil as well as removing it from the superview but both didn't work.

func updateSearchResultsForSearchController(searchController: UISearchController) {
     //code for filtering search results here

     //tableView.tableHeaderView = nil
     //tableView.tableHeaderView?.removeFromSuperview()
     tableView.reloadData()
}

override func tableView(tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
    return nil
}