docs: def _init_table(self):
          """
          Initialize the observation table.
          """
          self.observation_table.sm_vector.append('')
          self.observation_table.smi_vector = list(self.alphabet)
          self.observation_table.em_vector = list(self.alphabet)
  
          for i in self.observation_table.em_vector:
              self._fill_table_entry('', i)
  
          for s, e in product(self.observation_table.smi_vector, self.observation_table.em_vector):
              self._fill_table_entry(s, e)