environment/lib/python2.7/site-packages/IPython/frontend/html/notebook/notebookmanager.py
def notebook_exists(self, notebook_id):
        """Does a notebook exist?"""
        if notebook_id not in self.mapping:
            return False
        path = self.get_path_by_name(self.mapping[notebook_id])
        return os.path.isfile(path)
def notebook_exists(self, notebook_id):
        """Does a notebook exist?"""
        if notebook_id not in self.mapping:
            return False
        path = self.get_path_by_name(self.mapping[notebook_id])
        return os.path.isfile(path)
Does a notebook exist?