'Make a deep copy this chart.
Formatters & display will be missing from the copy, due to limitations in
deepcopy.'

def _Clone(self):

    orig_values = {}
    uncopyables = ['formatters', 'display', 'auto_color', 'auto_scale', 'auto_legend']
    for name in uncopyables:
        orig_values[name] = getattr(self, name)
        setattr(self, name, None)
    clone = copy.deepcopy(self)
    for (name, orig_value) in orig_values.iteritems():
        setattr(self, name, orig_value)
    return clone
