@classmethod
def from_data(cls, data, root=None, keypath=tuple()):
    """
        Alternate constructor for 'baby' DataProxies used as sub-dict values.

        Allows creating standalone DataProxy objects while also letting
        subclasses like `.Config` define their own ``__init__`` without
        muddling the two.

        :param dict data:
            This particular DataProxy's personal data. Required, it's the Data
            being Proxied.

        :param root:
            Optional handle on a root DataProxy/Config which needs notification
            on data updates.

        :param tuple keypath:
            Optional tuple describing the path of keys leading to this
            DataProxy's location inside the ``root`` structure. Required if
            ``root`` was given (and vice versa.)

        .. versionadded:: 1.0
        """
    obj = cls()
    obj._set(_config=data)
    obj._set(_root=root)
    obj._set(_keypath=keypath)
    return obj
