code: def test_selector(self):
      d = {"col1": [f"{i}" for i in range(31)], "col2": ["a"] * 31}
      df = pd.DataFrame(data=d)
  
      self.assertEqual(
          EncodingSelector.get(df, None, "col1"),
          PreprocessingCategorical.MANY_CATEGORIES,
      )
      self.assertEqual(
          EncodingSelector.get(df, None, "col2"),
          PreprocessingCategorical.FEW_CATEGORIES,
      )
  
file_path: mljar-supervised/tests/tests_preprocessing/test_encoding_selector.py
imports: import unittest
  import tempfile
  import numpy
  import pandas
  from supervised.preprocessing.encoding_selector import EncodingSelector
  from supervised.preprocessing.preprocessing_categorical import PreprocessingCategorical
label_desc: Use image node_id 1 for calling the CategoricalIntegersTest obj's underlying member method code with example usage: obj.test_selector() without return types