code: def ackley(x: np.ndarray) -> float:
      dim = x.size
      sum_cos = np.sum(np.cos(2 * np.pi * x))
      return (
          -20.0 * exp(-0.2 * sqrt(sphere(x) / dim))
          - exp(sum_cos / dim)
          + 20
          + exp(1)
      )
  
imports: from math import exp, sqrt, tanh
  import numpy
  import nevergrad.common.typing
  from nevergrad.common.decorators import Registry
label_desc: Use image node_id 23 for calling a global function with example usage: ackley(x) and returns: unknown