code: def test_optimizer_exceptions():
      r"""Test exceptions from SyN"""
      # An arbitrary valid metric
      metric = metrics.SSDMetric(2)
      # The metric must not be None
      assert_raises(
          ValueError, imwarp.SymmetricDiffeomorphicRegistration, None
      )
      # The iterations list must not be empty
      assert_raises(
          ValueError,
          imwarp.SymmetricDiffeomorphicRegistration,
          metric,
          [],
      )
  
      optimizer = imwarp.SymmetricDiffeomorphicRegistration(
          metric, None
      )
      # Verify the default iterations list
      assert_array_equal(optimizer.level_iters, [100, 100, 25])
  
      # Verify exception thrown when attempting to fit the energy profile without
      # enough data
      assert_raises(ValueError, optimizer._get_energy_derivative)
      assert_raises(ValueError, optimizer.get_map)
  
imports: import numpy
  import nibabel.eulerangles
  from numpy.testing import assert_equal, assert_array_equal, assert_array_almost_equal, assert_raises
  from dipy.core.interpolation import interpolate_scalar_2d, interpolate_scalar_3d
  from dipy.data import get_fnames
  from dipy.align import floating
  from dipy.align import imwarp
  from dipy.align import metrics
  from dipy.align import vector_fields
  from dipy.align import VerbosityLevels
  from dipy.align.imwarp import DiffeomorphicMap
  from dipy.tracking.streamline import deform_streamlines
  from dipy.testing.decorators import set_random_number_generator
label_desc: Use image node_id 5 for calling a global function with example usage: test_optimizer_exceptions() without return types