code: def _wikipedia_example_hmm():
      # Example from wikipedia
      # (https://en.wikipedia.org/wiki/Forward%E2%80%93backward_algorithm)
  
      states = ["rain", "no rain"]
      symbols = ["umbrella", "no umbrella"]
  
      A = [[0.7, 0.3], [0.3, 0.7]]  # transition probabilities
      B = [[0.9, 0.1], [0.2, 0.8]]  # emission probabilities
      pi = [0.5, 0.5]  # initial probabilities
  
      seq = [
          "umbrella",
          "umbrella",
          "no umbrella",
          "umbrella",
          "umbrella",
      ]
      seq = list(zip(seq, [None] * len(seq)))
  
      model = hmm._create_hmm_tagger(states, symbols, A, B, pi)
      return model, states, symbols, seq
  
imports: import pytest
  from nltk.tag import hmm
label_desc: Use image node_id 1 for calling a global function with example usage: _wikipedia_example_hmm() and returns: model,  states,  symbols,  seq