class_docstr: Test PFMFeaturizer.
docstr: Test PFM featurizer for simple MSA.
docstr_tok: ["Test","PFM","featurizer","for","simple","MSA","."]
code: def test_PFMFeaturizer_arbitrary(self):
      """
      Test PFM featurizer for simple MSA.
      """
      pfm = self.featurizer.featurize(self.msa)
      assert pfm.shape == (2, len(CHARSET) + 1, self.max_length)
      assert pfm[0][0][0] == 1
  
file_path: deepchem/deepchem/feat/tests/test_position_frequency_matrix_featurizer.py
imports: import unittest
  import numpy
  from deepchem.feat.sequence_featurizers.position_frequency_matrix_featurizer import PFMFeaturizer, CHARSET, PFM_to_PPM
label_desc: Use image node_id 2 for calling the TestPFMFeaturizer obj's underlying member method code with example usage: obj.test_PFMFeaturizer_arbitrary() without return types