@observe('sphinxify_docstring')
def _sphinxify_docstring_changed(self, change):
    if change['new']:
        warn('`sphinxify_docstring` is provisional since IPython 5.0 and might change in future versions.', ProvisionalWarning)
@observe('sphinxify_docstring')
def _sphinxify_docstring_changed(self, change):
    if change['new']:
        warn('`sphinxify_docstring` is provisional since IPython 5.0 and might change in future versions.', ProvisionalWarning)