code: def get_sos_step_steps(stmt):
      '''
      Extract sos_step(x) from statement
      '''
      opt_values = get_param_of_function(
          'sos_step', stmt, extra_dict=env.sos_dict.dict())
      for value in opt_values:
          if len(value) != 1:
              raise ValueError('sos_step only accept one and only one parameter')
      return [x[0] for x in opt_valuesf get_sos_step_steps(stmt):
      '''
      Extract sos_step(x) from statement
      '''
      opt_values = get_param_of_function(
          'sos_step', stmt, extra_dict=env.sos_dict.dict())
      for value in opt_values:
          if len(value) != 1:
              raise ValueError('sos_step only accept one and only one parameter')
      return [x[0] for x in opt_values]
docs: Extract sos_step(x) from statement