_utils

"""Utility functions for middleware."""

from langchain_core.messages import SystemMessage

def append_to_system_message( system_message: SystemMessage | None, text: str, ) -> SystemMessage: """Append text to a system message.

Args:
    system_message: Existing system message or None.
    text: Text to add to the system message.

Returns:
    New SystemMessage with the text appended.
"""
new_content: list[str | dict[str, str]] = list(system_message.content_blocks) if system_message else []
if new_content:
    text = f"\n\n{text}"
new_content.append({"type": "text", "text": text})
return SystemMessage(content=new_content)