input: Write a function to filter a list of email addresses to return only those that belong to a specified domain. The function should take two arguments: the list of email addresses and the domain to filter by. If the input list is empty, 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(["alice@hotmail.com", "daniel@outlook.com"], "yahoo.com")==[]
  assert filter_emails([], "gmail.com")==[]
  assert filter_emails(["john@gmail.com"], "gmail.com")==["john@gmail.com"]
output: def filter_emails(emails, domain):
      return [email for email in emails if email.endswith(f"@{domain}")]