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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 from_dict(cls, d):
 """ Construct a MSONable AdfKey object from the JSON dict. Parameters d : dict A dict of saved attributes. Returns ------- adfkey : AdfKey An AdfKey object recovered from the JSON dict ``d``. """

        key = d.get("name")
        options = d.get("options", None)
        subkey_list = d.get("subkeys", [])
        if len(subkey_list) > 0:
            subkeys = list(map(lambda k: AdfKey.from_dict(k), subkey_list))
        else:
            subkeys = None
        return cls(key, options, subkeys)