docstr: Check the exception when input is not an integer.
code: def test_flatten_batch_to_2d_exception_raised_types(self):
      """Check the exception when input is not an integer."""
      with self.assertRaisesRegexp(
          TypeError, "'sizes' must have an integer type."
      ):
          utils.flatten_batch_to_2d(np.ones((3, 4, 3)), np.ones((3,)))
  
imports: from absl.testing import parameterized
  import numpy
  from scipy import linalg
  import tensorflow
  from tensorflow_graphics.geometry.convolution import utils
  from tensorflow_graphics.util import test_case
label_desc: Use image node_id 2 for calling the UtilsFlattenBatchTo2dTests obj's underlying member method code with example usage: obj.test_flatten_batch_to_2d_exception_raised_types() without return types