abstract save function to base index class (#39)

gpt_index/indices/base.py

 """Base data structure classes."""
+import json
 from abc import abstractmethod
 from typing import Any, Generic, List, Optional, TypeVar, cast
 
@@ -92,6 +93,7 @@ class BaseGPTIndex(Generic[IS]):
     def load_from_disk(cls, save_path: str, **kwargs: Any) -> "BaseGPTIndex":
         """Load from disk."""
 
-    @abstractmethod
     def save_to_disk(self, save_path: str) -> None:
         """Safe to file."""
+        with open(save_path, "w") as f:
+            json.dump(self.index_struct.to_dict(), f)

gpt_index/indices/keyword_table/__init__.py

+"""Init file."""

gpt_index/indices/list/__init__.py

+"""Init file."""

gpt_index/indices/list/base.py

@@ -72,8 +72,3 @@ class GPTListIndex(BaseGPTIndex[IndexList]):
         """Load from disk."""
         with open(save_path, "r") as f:
             return cls(index_struct=IndexList.from_dict(json.load(f)), **kwargs)
-
-    def save_to_disk(self, save_path: str) -> None:
-        """Safe to file."""
-        with open(save_path, "w") as f:
-            json.dump(self.index_struct.to_dict(), f)

gpt_index/indices/tree/__init__.py

+"""Init file."""

gpt_index/indices/tree/base.py

@@ -136,8 +136,3 @@ class GPTTreeIndex(BaseGPTIndex[IndexGraph]):
         """Load from disk."""
         with open(save_path, "r") as f:
             return cls(index_struct=IndexGraph.from_dict(json.load(f)), **kwargs)
-
-    def save_to_disk(self, save_path: str) -> None:
-        """Safe to file."""
-        with open(save_path, "w") as f:
-            json.dump(self.index_struct.to_dict(), f)

pyproject.toml

@@ -4,4 +4,4 @@ profile = "black"
 [tool.mypy]
 ignore_missing_imports = "True"
 disallow_untyped_defs = "True"
-exclude = ["notebooks"]
\ No newline at end of file
+exclude = ["notebooks", "build"]
\ No newline at end of file