code: def project_l1_ball(v, z=1):
      return np.sign(v) * project_simplex(np.abs(v), z)
  
imports: import numpy
  from scipy.linalg import svd
  from lightning.impl.prox_fast import prox_tv1d
label_desc: Use image node_id 2 for calling a global function with example usage: project_l1_ball(v, z) and returns: unknown