Sort the proxy model

        :returns: None
        :rtype: None
        :raises: None

def sort_model(self, *args, **kwargs):
        """Sort the proxy model

        :returns: None
        :rtype: None
        :raises: None
        """
        self.proxy.sort(17)  # sort the identifier
        self.proxy.sort(2)  # sort the element
        self.proxy.sort(1)  # sort the elementgrp
        self.proxy.sort(0)