Fetch and return a proper ClientApproval object.

def Get(self):
    """Fetch and return a proper ClientApproval object."""

    args = user_pb2.ApiGetClientApprovalArgs(
        client_id=self.client_id,
        approval_id=self.approval_id,
        username=self.username)
    result = self._context.SendRequest("GetClientApproval", args)
    return ClientApproval(
        data=result, username=self._context.username, context=self._context)