'Display the possible completions'

def show_completion_list(self, completions, completion_text='', automatic=True):

    if (not completions):
        return
    if (not isinstance(completions[0], tuple)):
        completions = [(c, '') for c in completions]
    if ((len(completions) == 1) and (completions[0][0] == completion_text)):
        return
    self.completion_text = completion_text
    underscore = set([(comp, t) for (comp, t) in completions if comp.startswith('_')])
    completions = sorted((set(completions) - underscore), key=(lambda x: str_lower(x[0])))
    completions += sorted(underscore, key=(lambda x: str_lower(x[0])))
    self.show_completion_widget(completions, automatic=automatic)
