code: def dV_dx(x):
      return x**3 - x
  
file_path: bokeh/examples/server/app/duffing_oscillator.py
imports: import numpy
  from bokeh.layouts import column, row
  from bokeh.models import ColumnDataSource, Div, Paragraph, Range1d, Slider
  from bokeh.plotting import curdoc, figure
label_desc: Use image node_id 1 for calling a global function with example usage: dV_dx(x) and returns: unknown