What is the right way to override the copy/deepcopy operations on an object in Python?
<p>So just to establish, I feel like I understand the difference between copy vs. deepcopy in the copy module and I've used copy.copy and copy.deepcopy before successfully, but this is the first time I've actually gone about overloading the __copy__ and __deepcopy__ methods.  I've already Googled around and looked through the built-in Python modules to look for instances of the __copy__ and __deepcopy__ functions (e.g. sets.py, decimal.py, and fractions.py), but I'm still not 100% sure I've got it right.</p>

<p>Here's my scenario: </p>

<p>I have a configuration object that mostly just consists of simple properties (though it will potentially have lists of other non-primitive objects in it).  Initially I'm going to instantiate one configuration object with a default set of values.  This configuration will be handed off to multiple other objects (to ensure all objects start with the same configuration).  Once user interaction starts, however, each object will need to be able to tweak the configurations independently without affecting each other's configurations (which says to me I'll need to make deepcopys of my initial configuration to hand around).</p>

<p>Here's a sample object:</p>

<pre><code>class ChartConfig(object):

    def __init__(self):

        #Drawing properties (Booleans/strings)
        self.antialiased = None
        self.plot_style = None
        self.plot_title = None
        self.autoscale = None

        #X axis properties (strings/ints)
        self.xaxis_title = None
        self.xaxis_tick_rotation = None
        self.xaxis_tick_align = None

        #Y axis properties (strings/ints)
        self.yaxis_title = None
        self.yaxis_tick_rotation = None
        self.yaxis_tick_align = None

        #A list of non-primitive objects
        self.trace_configs = []

    def __copy__(self):
        pass

    def __deepcopy__(self, memo):
        pass
</code></pre>

<p>What is the right way to implement the copy and deepcopy methods on this object to ensure copy.copy and copy.deepcopy give me the proper behavior?  I'm currently using Python 2.6.2.  </p>

<p>Thanks in advance!</p>
