code: def update(ind):
      ykeys = (k for k in lines_source.data.keys() if k.startswith("y"))
      lines_source.data.update(
          {y: roll(lines_source.data[y], -1) for y in ykeys}
      )
      items_source.data.update(update_term_data(ind))
  
file_path: bokeh/examples/server/app/fourier_animated.py
imports: from numpy import array, cos, cumsum, hstack, linspace, pi, roll, sin
  from bokeh.driving import repeat
  from bokeh.io import curdoc
  from bokeh.layouts import column
  from bokeh.models import CDSView, ColumnDataSource, IndexFilter
  from bokeh.plotting import figure
label_desc: Use image node_id 2 for calling a global function with example usage: update(ind) without return types