Traceback (most recent call last):
  File "/usr/share/solfege/src/mainwin.py", line 457, in <lambda>
    lambda o, e=lesson_id: self.m_app.practise_lesson_id(e)))
  File "/usr/share/solfege/src/app.py", line 226, in practise_lesson_id
    self.m_ui.box_dict[module].on_start_practise()
  File "/usr/share/solfege/src/idbyname.py", line 333, in on_start_practise
    self.update_answer_buttons()
  File "/usr/share/solfege/src/idbyname.py", line 162, in update_answer_buttons
    self.g_bb.ask_for_names_changed()
TypeError: 'NoneType' object is not callable