code: def change_bollinger_bands_state(self, new_state):
      self.show_bollinger_bands = new_state
      if self.bands and self.selected:
          self.bands.visible = new_state
  
file_path: coach/rl_coach/dashboard_components/signals.py
imports: import random
  import numpy
  from bokeh.models import ColumnDataSource
  from bokeh.palettes import Dark2
  from rl_coach.dashboard_components.globals import show_spinner, hide_spinner, current_color
  from rl_coach.utils import squeeze_list
label_desc: Use image node_id 8 for calling the Signal obj's underlying member method code with example usage: obj.change_bollinger_bands_state(new_state) without return types