code: def mag(a):
      return _sqrt(a[0] ** 2 + a[1] ** 2 + a[2] ** 2)
  
file_path: sympy/sympy/plotting/pygletplot/plot_rotation.py
imports: import pyglet.gl
  from math import sqrt, acos
label_desc: Use image node_id 3 for calling a global function with example usage: mag(a) and returns: _sqrt