@classmethod
def encode_values(cls, entry_payload):
    """Encode all entries of all lists in dictionary to bytes."""
    encoded_dict = {}
    for key, list in entry_payload.items():
        encoded_list = []
        for entry in list:
            encoded_list.append(entry.encode('utf-8'))
            encoded_dict[key] = encoded_list
    return encoded_dict
