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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 _combine_args(self):
 """Sets protected data by combining raw data set from the constructor. If a ``_parent`` is set, updates the ``_flat_path`` and sets the ``_namespace`` and ``_project`` if not already set. :rtype: :class:`list` of :class:`dict` :returns: A list of key parts with kind and ID or name set. :raises: :class:`ValueError` if the parent key is not complete. """

        child_path = self._parse_path(self._flat_path)

        if self._parent is not None:
            if self._parent.is_partial:
                raise ValueError("Parent key must be complete.")

            # We know that _parent.path() will return a copy.
            child_path = self._parent.path + child_path
            self._flat_path = self._parent.flat_path + self._flat_path
            if (
                self._namespace is not None
                and self._namespace != self._parent.namespace
            ):
                raise ValueError("Child namespace must agree with parent's.")
            self._namespace = self._parent.namespace
            if self._project is not None and self._project != self._parent.project:
                raise ValueError("Child project must agree with parent's.")
            self._project = self._parent.project

        return child_path