from langchain.schema import HumanMessage, AIMessage, SystemMessage

def convert_dict_messages(dict_messages):
    message_objs = []
    for msg in dict_messages:
        role = msg.get("role")
        content = msg.get("content", "")
        
        if role == "user":
            message_objs.append(HumanMessage(content=content))
        elif role == "assistant":
            message_objs.append(AIMessage(content=content))
        elif role == "system":
            message_objs.append(SystemMessage(content=content))
        else:
            raise ValueError(f"Unknown role: {role}")
    
    return message_objs