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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 update_not_existing_kwargs(to_update, update_from):
 """ This function updates the keyword aguments from update_from in to_update, only if the keys are not set in to_update. This is used for updated kwargs from the default dicts. """

    if to_update is None:
        to_update = {}
    to_update.update({k:v for k,v in update_from.items() if k not in to_update})
    return to_update