class_docstr: This is for testing callbacks.
class_docstr_tok: ["This","is","for","testing","callbacks","."]
code: def __call__(self, x):
      self.count += 1
      if self.accum is None:
          self.accum = np.array(x)
      else:
          self.accum += x
  
file_path: catboost/contrib/python/scipy/py3/scipy/optimize/tests/test_trustregion.py
imports: import itertools
  from copy import deepcopy
  import numpy
  from numpy.testing import assert_, assert_equal, assert_allclose
  from scipy.optimize import minimize, rosen, rosen_der, rosen_hess, rosen_hess_prod, BFGS
  from scipy.optimize._differentiable_functions import FD_METHODS
  import pytest
label_desc: Use image node_id 2 for calling the Accumulator obj's underlying member method code with example usage: obj.__call__(x) without return types