code: def test_gap_filling_forward_correct(get_time_series: Callable):
      """
      Goal: check that assimilation different time series does not leads to errors
      and missing values presence
      """
      arr_with_gaps = get_time_series()
  
      linear_pipeline = get_simple_ts_pipeline(model_root="linear")
      gapfiller = ModelGapFiller(
          gap_value=-100, pipeline=linear_pipeline
      )
      without_gap = gapfiller.forward_filling(arr_with_gaps)
  
      assert len(np.ravel(np.argwhere(without_gap == -100))) == 0
  
imports: import numpy
  import pytest
  from sklearn.metrics import mean_squared_error
  from typing import Callable
  from examples.simple.time_series_forecasting.gapfilling import get_array_with_gaps
  from fedot.utilities.ts_gapfilling import ModelGapFiller, SimpleGapFiller
  from test.unit.tasks.test_forecasting import get_simple_ts_pipeline
label_desc: Use image node_id 13 for calling a global function with example usage: test_gap_filling_forward_correct(get_time_series) without return types