code: def angle(a, b):
      """Compute dot product between vectors `a` and `b`.
  
      The arccos of the return value would give an actual angle.
      """
      # anorm = (a**2).sum()**0.5
      # bnorm = (b**2).sum()**0.5
      return (a * b).sum()
  
imports: import numpy
  from numpy.linalg import norm
  import matplotlib.pyplot
label_desc: Use image node_id 9 for calling a global function with example usage: angle(a, b) and returns: unknown