fix: add import BaseModel to timeseries models

Author: fabclmnt

src/ydata_synthetic/synthesizers/base.py

@@ -36,8 +36,8 @@ def __init__(self,
                   cat_cols: Optional[List[str]] = None,
                   **kwargs):
         warn(
-            f"{self.__class__.__name__} is deprecated. Please leverage ydata-sdk RegularSynthesizer or TimeSeriesSynthesizer instead. For more information, "
-            f"check ydata-sdk documentation:  https://docs.fabric.ydata.ai/latest/sdk/examples/synthesize_tabular_data/.",
+            f"{self.__class__.__name__} is deprecated. Please leverage ydata-sdk **RegularSynthesizer** or **TimeSeriesSynthesizer** instead. For more information, "
+            f"check ydata-sdk documentation:  https://docs.fabric.ydata.ai/latest/sdk/examples/.",
             DeprecationWarning,
             stacklevel=2
         )

src/ydata_synthetic/synthesizers/timeseries/doppelganger/model.py

@@ -1,6 +1,7 @@
 """
     Doppelganger implementation file
 """
+from ydata_synthetic.synthesizers.base import BaseModel
 
 class DoppelGANgerNetwork(BaseModel):
     """

src/ydata_synthetic/synthesizers/timeseries/timegan/model.py

@@ -1,6 +1,7 @@
 """
     TimeGAN file definition
 """
+from ydata_synthetic.synthesizers.base import BaseModel
 
 class TimeGAN(BaseModel):
     """