Fix #340 example llm_extraction (#358)

@Haopeng138 Thank you so much. They are still part of the library. I forgot to update them since I moved the asynchronous versions years ago. I really appreciate it. I have to say that I feel weak in the documentation. That's why I spent a lot of time on it last week. Now, when you mention some of the things in the example folder, I realize I forgot about the example folder. I'll try to update it more. If you find anything else, please help and support. Thank you. I will add your name to contributor name as well.

docs/examples/llm_extraction_openai_pricing.py

@@ -1,23 +1,21 @@
-import os
-import time
-from crawl4ai.web_crawler import WebCrawler
-from crawl4ai.chunking_strategy import *
 from crawl4ai.extraction_strategy import *
 from crawl4ai.crawler_strategy import *
+import asyncio
+from pydantic import BaseModel, Field
 
 url = r'https://openai.com/api/pricing/'
 
-crawler = WebCrawler()
-crawler.warmup()
-
-from pydantic import BaseModel, Field
-
 class OpenAIModelFee(BaseModel):
     model_name: str = Field(..., description="Name of the OpenAI model.")
     input_fee: str = Field(..., description="Fee for input token for the OpenAI model.")
     output_fee: str = Field(..., description="Fee for output token for the OpenAI model.")
 
-result = crawler.run(
+from crawl4ai import AsyncWebCrawler
+
+async def main():
+    # Use AsyncWebCrawler
+    async with AsyncWebCrawler() as crawler:
+        result = await crawler.arun(
             url=url,
             word_count_threshold=1,
             extraction_strategy= LLMExtractionStrategy(
@@ -30,12 +28,13 @@ result = crawler.run(
                             'One extracted model JSON format should look like this: ' \
                             '{ "model_name": "GPT-4", "input_fee": "US$10.00 / 1M tokens", "output_fee": "US$30.00 / 1M tokens" }'
             ),
-    bypass_cache=True,
+
         )
-
+        print("Success:", result.success)
         model_fees = json.loads(result.extracted_content)
-
         print(len(model_fees))
 
         with open(".data/data.json", "w", encoding="utf-8") as f:
             f.write(result.extracted_content)
+
+asyncio.run(main())