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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def deep_update(source, overrides):
 """Update a nested dictionary or similar mapping. Modify ``source`` in place. :type source: collections.Mapping :type overrides: collections.Mapping :rtype: collections.Mapping """

    for key, value in overrides.items():
        if isinstance(value, collections.Mapping) and value:
            returned = deep_update(source.get(key, {}), value)
            source[key] = returned
        else:
            source[key] = overrides[key]
    return source