code: def test_initialize_fields(self):
      self.assertRaises(TypeError, dedupe.api.ActiveMatching)
  
      with self.assertRaises(ValueError):
          dedupe.api.ActiveMatching(
              [],
          )
  
      with self.assertRaises(ValueError):
          dedupe.api.ActiveMatching(
              [
                  {
                      "field": "name",
                      "type": "Custom",
                      "comparator": lambda x, y: 1,
                  }
              ],
          )
  
      with self.assertRaises(ValueError):
          dedupe.api.ActiveMatching(
              [
                  {
                      "field": "name",
                      "type": "Custom",
                      "comparator": lambda x, y: 1,
                  },
                  {
                      "field": "age",
                      "type": "Custom",
                      "comparator": lambda x, y: 1,
                  },
              ],
          )
  
      dedupe.api.ActiveMatching(
          [
              {
                  "field": "name",
                  "type": "Custom",
                  "comparator": lambda x, y: 1,
              },
              {"field": "age", "type": "String"},
          ],
      )
  
file_path: dedupe/tests/test_api.py
imports: import itertools
  import unittest
  import warnings
  from collections import OrderedDict
  import dedupe.api
label_desc: Use image node_id 2 for calling the ActiveMatch obj's underlying member method code with example usage: obj.test_initialize_fields() without return types