'Attach a model to a Bokeh |Document|.
This private interface should only ever called by the Document
implementation to set the private ._document field properly'

def _attach_document(self, doc):

    if ((self._document is not None) and (self._document is not doc)):
        raise RuntimeError(('Models    must    be    owned    by    only    a    single    document,    %r    is    already    in    a    doc' % self))
    doc.theme.apply_to_model(self)
    self._document = doc
    self._update_event_callbacks()
