diff --git a/redkg/visualization/contracts/base_graph_contract.py b/redkg/visualization/contracts/base_graph_contract.py
index 9670780..92ac35c 100644
--- a/redkg/visualization/contracts/base_graph_contract.py
+++ b/redkg/visualization/contracts/base_graph_contract.py
@@ -1,6 +1,6 @@
 """BaseGraphContract module."""
 
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 from typing import Any, Optional, Union
 
 from redkg.visualization.config.types import TGraphEdgeList
@@ -12,4 +12,4 @@ class BaseGraphContract:
 
     vertex_num: int
     edge_list: tuple[Any, list[float]]
-    edge_weights: Optional[Union[float, list[float]]]
+    edge_weights: Optional[Union[float, list[float]]] = field(default_factory=list)
diff --git a/redkg/visualization/contracts/base_visualization_contract.py b/redkg/visualization/contracts/base_visualization_contract.py
index 4f01348..9b8946f 100644
--- a/redkg/visualization/contracts/base_visualization_contract.py
+++ b/redkg/visualization/contracts/base_visualization_contract.py
@@ -1,6 +1,6 @@
 """BaseVisualizationContract module."""
 
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 from typing import Any, Iterable, Optional, Union
 
 from redkg.visualization.config.parameters.defaults import Defaults
@@ -14,7 +14,7 @@ class BaseVisualizationContract:
     edge_color: Union[str, list] = Defaults.edge_color
     edge_fill_color: Union[str, list[Any]] = Defaults.edge_fill_color
     edge_line_width: Union[float, list[Any]] = Defaults.edge_line_width
-    vertex_label: Union[list[str], Iterable[str]] = []
+    vertex_label: Union[list[str], Iterable[str]] = field(default_factory=list)
     vertex_size: Union[float, list] = Defaults.vertex_size
     vertex_color: Union[str, list] = Defaults.vertex_color
     vertex_line_width: Union[float, list] = Defaults.vertex_line_width
diff --git a/redkg/visualization/contracts/size_constructor_contract.py b/redkg/visualization/contracts/size_constructor_contract.py
index a2e31ae..17c4da6 100644
--- a/redkg/visualization/contracts/size_constructor_contract.py
+++ b/redkg/visualization/contracts/size_constructor_contract.py
@@ -1,6 +1,6 @@
 """SizeConstructorContract module."""
 
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 from typing import Sized, Union
 
 from redkg.visualization.config.parameters.defaults import Defaults
@@ -12,7 +12,7 @@ class SizeConstructorContract:
     """Size сonstructor сontract base class."""
 
     vertex_num: int
-    edge_list: Union[TEdgeList, list, Sized] = []
+    edge_list: Union[TEdgeList, list, Sized] = field(default_factory=list)
     vertex_size: Union[float, list] = Defaults.vertex_size
     vertex_line_width: Union[float, list] = Defaults.vertex_line_width
     edge_line_width: Union[float, list] = Defaults.edge_line_width