code: def testCoreInterfaceIntInputData(self):
      agglomerative_instance = agglomerative(
          [[1], [2], [3], [20], [21], [22]],
          2,
          type_link.SINGLE_LINK,
          True,
      )
      agglomerative_instance.process()
      assert len(agglomerative_instance.get_clusters()) == 2
  
imports: import unittest
  import matplotlib
  from pyclustering.cluster.tests.agglomerative_templates import AgglomerativeTestTemplates
  from pyclustering.cluster.agglomerative import agglomerative, type_link
  from pyclustering.samples.definitions import SIMPLE_SAMPLES
  from pyclustering.core.tests import remove_library, corrupt_library
label_desc: Use image node_id 25 for calling the AgglomerativeIntegrationTest obj's underlying member method code with example usage: obj.testCoreInterfaceIntInputData() without return types