input: Write a python function to extract the sender's email address from an email message using regex.
  assert extract_sender_email(""" 
  From: "John Doe" <john.doe@example.com>
  To: "Jane Doe" <jane.doe@example.com>
  Subject: Example Email
  """) == 'john.doe@example.com'
  assert extract_sender_email(""" 
  From: "Alice Smith" <alice.smith@example.org>
  To: "Bob Brown" <bob.brown@example.org>
  Subject: Test Email
  """) == 'alice.smith@example.org'
  assert extract_sender_email(""" 
  From: "Charlie Black" <charlie.black@example.net>
  To: "Eve White" <eve.white@example.net>
  Subject: Another Test Email
  """) == 'charlie.black@example.net'
output: import re
  
  def extract_sender_email(email_message):
      match = re.search(r'From: .*?<(.*?)>', email_message)
      if match:
          return match.group(1)
      return None