input: Write a function to extract all email addresses from a given string using a regular expression. The function should return a list of all the extracted email addresses.
  assert find_emails("This is an example with two emails: john@example.com, and jane@example.com")==["john@example.com", "jane@example.com"]
  assert find_emails("No emails here")==[]
  assert find_emails("")==[]
  assert find_emails("email1@example.com, email2@example.com, email3@example.com")==["email1@example.com", "email2@example.com", "email3@example.com"]
  assert find_emails("Mixed text with email: test@test.com in the middle")==["test@test.com"]
output: import re
  
  def find_emails(text):
      return re.findall(r'[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}', text)