input: Write a python function to fetch HTML content from a given URL.
  assert fetch_html("https://example.com") == "<!doctype html><html>...</html>"
  assert fetch_html("https://httpbin.org/html") == "<!DOCTYPE html>\n<html>...</html>"
  assert fetch_html("https://www.example.org") == "<!doctype html><html>...</html>"
output: import requests
  
  def fetch_html(url):
      response = requests.get(url)
      return response.text