input: Write a function to extract all email addresses from a given string using a regular expression. If the given string is empty then return an empty list.
  def find_emails(text):
      regex = r"([a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+)"
      emails = re.findall(regex, text)
      return emails
  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("Contact us at: support@example.org for more information.") == ["support@example.org"]
  assert find_emails("There are no emails in this string.") == []
  assert find_emails("") == []
output: def find_emails(text):
      import re
      regex = r"([a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+)"
      emails = re.findall(regex, text)
      return emails