code: def update(attr, old, new):
      out = image.copy()
      blur(out, image, 2 * new + 1)
      source.data.update(image=[out])
  
file_path: bokeh/examples/server/app/image_blur.py
imports: import numpy
  import scipy.datasets
  from bokeh.io import curdoc
  from bokeh.layouts import column
  from bokeh.models import ColumnDataSource, Slider
  from bokeh.palettes import gray
  from bokeh.plotting import figure
label_desc: Use image node_id 2 for calling a global function with example usage: update(attr, old, new) without return types