seaborn introduction

[lauradls]

@A1anZhu Given that this PR was submitted from the main branch, please follow the instructions below to correct it:

• Close this PR.
• Follow the instructions here for forgetting to branch if you committed and pushed to GitHub: https://edav.info/github#fixing-mistakes
• If you have trouble with 2., then delete the local folder of the project, delete your fork on GitHub, and start over.
• Open a new PR.