Get the dictionary of valid completions

def setup_completer(cls):
        "Get the dictionary of valid completions"
        try:
            for element in Store.options().keys():
                options = Store.options()['.'.join(element)]
                plotkws = options['plot'].allowed_keywords
                stylekws = options['style'].allowed_keywords
                dotted = '.'.join(element)
                cls._completions[dotted] = (plotkws, stylekws if stylekws else [])
        except KeyError:
            pass
        return cls._completions