refactor: remove LangChain wrappers

Author: f-aguzzi

scrapegraphai/nodes/generate_answer_node.py

@@ -6,9 +6,10 @@
 from langchain.prompts import PromptTemplate
 from langchain_core.output_parsers import JsonOutputParser
 from langchain_core.runnables import RunnableParallel
+from langchain_openai import ChatOpenAI
+from langchain_community.chat_models import ChatOllama
 from tqdm import tqdm
 from ..utils.logging import get_logger
-from ..models import Ollama, OpenAI
 from .base_node import BaseNode
 from ..helpers import template_chunks, template_no_chunks, template_merge, template_chunks_md, template_no_chunks_md, template_merge_md
 
@@ -41,7 +42,7 @@ def __init__(
 
         self.llm_model = node_config["llm_model"]
 
-        if isinstance(node_config["llm_model"], Ollama):
+        if isinstance(node_config["llm_model"], ChatOllama):
             self.llm_model.format="json"
 
         self.verbose = (
@@ -93,7 +94,7 @@ def execute(self, state: dict) -> dict:
 
         format_instructions = output_parser.get_format_instructions()
 
-        if  isinstance(self.llm_model, OpenAI) and not self.script_creator or self.force and not self.script_creator or self.is_md_scraper:
+        if  isinstance(self.llm_model, ChatOpenAI) and not self.script_creator or self.force and not self.script_creator or self.is_md_scraper:
             template_no_chunks_prompt = template_no_chunks_md
             template_chunks_prompt = template_chunks_md
             template_merge_prompt = template_merge_md