Data preparation and analysis for chat model fine-tuning

# Data preparation and analysis for chat model fine-tuning This notebook serves as a tool to preprocess and analyze the chat dataset used for fine-tuning a chat model. It checks for format errors, provides basic statistics, and estimates token counts for fine-tuning costs. The method shown here corresponds to the [current fine-tuning method](https://platform.openai.com/docs/guides/fine-tuning) for gpt-3.5-turbo. See [legacy fine-tuning](https://platform.openai.com/docs/guides/legacy-fine-tuning) for models like babbage-002 and davinci-002.