code: def solver(func, A, b, M=None, atol=0.0, **kwargs):
      x, _ = func(A, b, atol=atol, M=M, **kwargs)
      return x
  
imports: from functools import partial
  import unittest
  from absl.testing import absltest
  import numpy
  import scipy.sparse.linalg
  import jax
  import jax.numpy
  import jax.scipy.sparse.linalg
  from jax import jit
  from jax import lax
  from jax.tree_util import register_pytree_node_class
  import jax._src.scipy.sparse.linalg
  from jax._src import config
  from jax._src import dtypes
  from jax._src import test_util
label_desc: Use image node_id 3 for calling a global function with example usage: solver(func, A, b, M, atol) and returns: x