opens a file dialog to get the path to a file and

def open_file_dialog(self):
        """
        opens a file dialog to get the path to a file and
        """
        dialog = QtGui.QFileDialog
        filename = dialog.getExistingDirectory(self, 'Select a file:', self.data_filepath.text())
        if str(filename)!='':
            self.data_filepath.setText(filename)