Fixed ModelDecomposeTransform import

CHANGELOG.md

@@ -51,7 +51,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - 
 
 ### Fixed
-- 
+- Fixed `ModelDecomposeTransform` import without `prophet` module ([#459](https://github.com/etna-team/etna/pull/459))
 - 
 - 
 - 

etna/transforms/decomposition/model_based.py

@@ -4,29 +4,40 @@
 
 import pandas as pd
 
+from etna import SETTINGS
 from etna.datasets import TSDataset
 from etna.datasets.utils import determine_num_steps
 from etna.models import BATSModel
 from etna.models import DeadlineMovingAverageModel
+from etna.models import HoltModel
 from etna.models import HoltWintersModel
-from etna.models import ProphetModel
 from etna.models import SARIMAXModel
 from etna.models import SeasonalMovingAverageModel
+from etna.models import SimpleExpSmoothingModel
 from etna.models import TBATSModel
 from etna.models.base import ContextRequiredModelType
 from etna.models.base import ModelType
 from etna.transforms import IrreversibleTransform
 
 _SUPPORTED_MODELS = Union[
     HoltWintersModel,  # full
-    ProphetModel,  # full
+    HoltModel,  # full
+    SimpleExpSmoothingModel,  # full
     SARIMAXModel,  # full
     DeadlineMovingAverageModel,  # need to account context/prediction size
     SeasonalMovingAverageModel,  # need to account context/prediction size
     BATSModel,  # dynamic components, not reliable
     TBATSModel,  # dynamic components, not reliable
 ]
 
+if SETTINGS.prophet_required:
+    from etna.models import ProphetModel
+
+    _SUPPORTED_MODELS = Union[  # type: ignore
+        _SUPPORTED_MODELS,
+        ProphetModel,  # full
+    ]
+
 
 class ModelDecomposeTransform(IrreversibleTransform):
     """Transform that uses ETNA models to estimate series decomposition.

tests/test_transforms/test_decomposition/test_model_based.py

@@ -6,10 +6,12 @@
 from etna.models import BATSModel
 from etna.models import CatBoostPerSegmentModel
 from etna.models import DeadlineMovingAverageModel
+from etna.models import HoltModel
 from etna.models import HoltWintersModel
 from etna.models import ProphetModel
 from etna.models import SARIMAXModel
 from etna.models import SeasonalMovingAverageModel
+from etna.models import SimpleExpSmoothingModel
 from etna.models import TBATSModel
 from etna.pipeline import Pipeline
 from etna.transforms import IForestOutlierTransform
@@ -253,6 +255,9 @@ def test_pipeline_models(ts_name, in_column, decompose_model, forecast_model, re
     "decompose_model",
     (
         HoltWintersModel(),
+        HoltModel(),
+        SimpleExpSmoothingModel(),
+        HoltWintersModel(trend="add", seasonal="add"),
         ProphetModel(),
         SARIMAXModel(),
         DeadlineMovingAverageModel(),