chore: import upstream snapshot with attribution

python/semantic_kernel/contents/kernel_content.py

@@ -0,0 +1,41 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+from abc import ABC, abstractmethod
+from typing import Annotated, Any, TypeVar
+
+from pydantic import Field
+
+from semantic_kernel.kernel_pydantic import KernelBaseModel
+
+_T = TypeVar("_T", bound="KernelContent")
+
+
+class KernelContent(KernelBaseModel, ABC):
+    """Base class for all kernel contents."""
+
+    # NOTE: if you wish to hold on to the inner content, you are responsible
+    # for saving it before serializing the content/chat history as it won't be included.
+    inner_content: Annotated[Any | None, Field(exclude=True)] = None
+    ai_model_id: str | None = None
+    metadata: dict[str, Any] = Field(default_factory=dict)
+
+    @abstractmethod
+    def __str__(self) -> str:
+        """Return the string representation of the content."""
+        pass
+
+    @abstractmethod
+    def to_element(self) -> Any:
+        """Convert the instance to an Element."""
+        pass
+
+    @classmethod
+    @abstractmethod
+    def from_element(cls: type[_T], element: Any) -> _T:
+        """Create an instance from an Element."""
+        pass
+
+    @abstractmethod
+    def to_dict(self) -> dict[str, Any]:
+        """Convert the instance to a dictionary."""
+        pass