update: add snake case

Author: VsevolodX

src/py/mat3ra/code/entity.py

@@ -2,7 +2,8 @@
 
 import jsonschema
 from mat3ra.utils import object as object_utils
-from pydantic import BaseModel
+from pydantic import BaseModel, ConfigDict
+from pydantic.alias_generators import to_snake
 from typing_extensions import Self
 
 from . import BaseUnderscoreJsonPropsHandler
@@ -86,6 +87,17 @@ def clone(self: T, extra_context: Optional[Dict[str, Any]] = None, deep=True) ->
         return self.model_copy(update=extra_context or {}, deep=deep)
 
 
+S = TypeVar("S", bound="InMemoryEntitySnakeCase")
+
+
+class InMemoryEntitySnakeCase(InMemoryEntityPydantic):
+    model_config = ConfigDict(
+        arbitrary_types_allowed=True,
+        alias_generator=to_snake,
+        populate_by_name=True,
+    )
+
+
 # TODO: remove in the next PR
 class InMemoryEntity(BaseUnderscoreJsonPropsHandler):
     jsonSchema: Optional[Dict] = None