def _set_is_copy(self, ref=None, copy=True):
    if (not copy):
        self._is_copy = None
    elif (ref is not None):
        self._is_copy = weakref.ref(ref)
    else:
        self._is_copy = None
def _set_is_copy(self, ref=None, copy=True):
    if (not copy):
        self._is_copy = None
    elif (ref is not None):
        self._is_copy = weakref.ref(ref)
    else:
        self._is_copy = None