'Load a chart from a pickle file'

def load_chart(self, *args):

    filename = askopenfilename(filetypes=self.CHART_FILE_TYPES, defaultextension='.pickle')
    if (not filename):
        return
    try:
        with open(filename, 'rb') as infile:
            chart = pickle.load(infile)
        self._chart = chart
        self._cv.update(chart)
        if self._matrix:
            self._matrix.set_chart(chart)
        if self._matrix:
            self._matrix.deselect_cell()
        if self._results:
            self._results.set_chart(chart)
        self._cp.set_chart(chart)
    except Exception as e:
        raise
        showerror('Error    Loading    Chart', ('Unable    to    open    file:    %r' % filename))
