def __init__(self, index=False, primary_key=False, default=None):
        """
        :param bool index: Use this field as an index. Indexed
            fields will support :py:meth:`Model.get` lookups.
        :param bool primary_key: Use this field as the primary key.
        """
        self._index = index or primary_key
        self._primary_key = primary_key
        self._default = default
def __init__ ( self , index = False , primary_key = False , default = None ) : self . _index = index or primary_key self . _primary_key = primary_key self . _default = default
:param bool index: Use this field as an index. Indexed
            fields will support :py:meth:`Model.get` lookups.
        :param bool primary_key: Use this field as the primary key.