code: def test_prediction_rangeindex_withstep():
      index = supported_increment_indexes[3][0]
      endog = pd.Series(dta[0], index=index)
      mod = tsa_model.TimeSeriesModel(endog)
  
      # Tests three common use cases: basic prediction, negative indexes, and
      # out-of-sample indexes.
  
      # Basic prediction: [0, end]
      start_key = 0
      end_key = None
      (
          start,
          end,
          out_of_sample,
          prediction_index,
      ) = mod._get_prediction_index(start_key, end_key)
  
      assert_equal(start, 0)
      assert_equal(end, nobs - 1)
      assert_equal(out_of_sample, 0)
      desired_index = pd.RangeIndex(start=0, stop=nobs * 6, step=6)
      assert_equal(prediction_index.equals(desired_index), True)
  
      # Negative index: [-2, end]
      start_key = -2
      end_key = -1
      (
          start,
          end,
          out_of_sample,
          prediction_index,
      ) = mod._get_prediction_index(start_key, end_key)
  
      assert_equal(start, 3)
      assert_equal(end, 4)
      assert_equal(out_of_sample, 0)
      desired_index = pd.RangeIndex(start=3 * 6, stop=nobs * 6, step=6)
      assert_equal(prediction_index.equals(desired_index), True)
  
      # Forecasting: [1, 5]
      start_key = 1
      end_key = nobs
      (
          start,
          end,
          out_of_sample,
          prediction_index,
      ) = mod._get_prediction_index(start_key, end_key)
  
      assert_equal(start, 1)
      assert_equal(end, 4)
      assert_equal(out_of_sample, 1)
      desired_index = pd.RangeIndex(
          start=1 * 6, stop=(nobs + 1) * 6, step=6
      )
      assert_equal(prediction_index.equals(desired_index), True)
  
      # Test getting a location that exists in the index
      loc, index, index_was_expanded = mod._get_index_loc(2)
      assert_equal(loc, 2)
      desired_index = pd.RangeIndex(start=0, stop=3 * 6, step=6)
      assert_equal(index.equals(desired_index), True)
      assert_equal(index_was_expanded, False)
  
imports: from statsmodels.compat.pandas import PD_LT_2_2_0, YEAR_END, is_int_index
  import warnings
  import numpy
  from numpy.testing import assert_equal, assert_raises
  import pandas
  import pytest
  from statsmodels.tools.sm_exceptions import ValueWarning
  from statsmodels.tsa.base import tsa_model
label_desc: Use image node_id 10 for calling a global function with example usage: test_prediction_rangeindex_withstep() without return types