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 particular domain. The function should take two parameters: the list of email addresses and the domain to filter by. If the given list is empty, the function should return an empty list.
  assert domain_filter(["john@gmail.com", "sarah@yahoo.com", "bob@microsoft.com", "sophie@gmail.com"], "gmail.com")==["john@gmail.com", "sophie@gmail.com"]
  assert domain_filter(["john@gmail.com", "sarah@yahoo.com", "bob@microsoft.com", "sophie@gmail.com"], "yahoo.com")==["sarah@yahoo.com"]
  assert domain_filter(["john@gmail.com", "sarah@yahoo.com", "bob@microsoft.com", "sophie@gmail.com"], "microsoft.com")==["bob@microsoft.com"]
  assert domain_filter(["john@gmail.com", "sophie@gmail.com"], "hotmail.com")==[]
  assert domain_filter([], "gmail.com")==[]
output: def domain_filter(emails, domain):
      return [email for email in emails if email.endswith(f"@{domain}")]