code: def arctan(z, rho, cost_only):
      rho[0] = np.arctan(z)
      if cost_only:
          return
      t = 1 + z**2
      rho[1] = 1 / t
      rho[2] = -2 * z / t**2
  
imports: from warnings import warn
  import numpy
  from numpy.linalg import norm
  from scipy.sparse import issparse
  from scipy.sparse.linalg import LinearOperator
  from scipy.optimize import _minpack, OptimizeResult
  from scipy.optimize._numdiff import approx_derivative, group_columns
  from scipy.optimize._minimize import Bounds
  from .trf import trf
  from .dogbox import dogbox
  from .common import EPS, in_bounds, make_strictly_feasible
label_desc: Use image node_id 9 for calling a global function with example usage: arctan(z, rho, cost_only) without return types