input: Write a function that takes a list of email addresses as input and returns a filtered list of email addresses that belong to a specified domain. The domain should be a parameter of the function. If no emails belong to the specified domain, the function should return an empty list.
  assert filter_emails(["john@gmail.com", "sarah@yahoo.com", "bob@microsoft.com", "sophie@gmail.com"], "gmail.com")==["john@gmail.com", "sophie@gmail.com"]
  assert filter_emails(["john@gmail.com", "sarah@yahoo.com", "bob@microsoft.com", "sophie@gmail.com"], "yahoo.com")==["sarah@yahoo.com"]
  assert filter_emails(["john@gmail.com", "sarah@yahoo.com", "bob@microsoft.com", "sophie@gmail.com"], "microsoft.com")==["bob@microsoft.com"]
  assert filter_emails(["john@gmail.com", "sarah@yahoo.com", "bob@microsoft.com", "sophie@gmail.com"], "hotmail.com")==[]
  assert filter_emails([], "gmail.com")==[]
output: def filter_emails(emails, domain):
      return [email for email in emails if email.endswith(f"@{domain}")]