code: def gaussian(x, amp, cen, wid):
      """1-d gaussian: gaussian(x, amp, cen, wid)"""
      return (amp / (sqrt(2 * pi) * wid)) * exp(
          -((x - cen) ** 2) / (2 * wid**2)
      )
  
imports: import matplotlib.pyplot
  from numpy import exp, loadtxt, pi, sqrt
  from lmfit import Model
label_desc: Use image node_id 1 for calling a global function with example usage: gaussian(x, amp, cen, wid) and returns: unknown