input: Write a function to filter phone numbers that start with '08'.
  assert filter_phone_numbers(['0834567', '0945678', '07123456', '08901234', '07890123']) == ['0834567', '08901234']
  assert filter_phone_numbers(['08123456', '08567890', '07123456']) == ['08123456', '08567890']
  assert filter_phone_numbers(['0945678', '07890123', '08765432', '08987654']) == ['08765432', '08987654']
output: def filter_phone_numbers(phone_numbers):
      return [number for number in phone_numbers if number.startswith('08')]