input: Write a function to extract all email addresses from a given string. If no email addresses are found, return an empty list. Return the email addresses as a list of strings.
  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("One email: alice@example.com")==['alice@example.com']
  assert find_emails("Multiple emails: bob@example.com, charlie@example.net")==['bob@example.com', 'charlie@example.net']
output: import re
  
  def find_emails(text):
      emails = re.findall(r'[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}', text)
      return emails