def prune_transfer_option(formats, language):
    """derive a unique list of transfer options.
    The unique character is based on identification language"""
    unique_transfer = []
    nil_reasons = ['missing', 'withheld', 'inapplicable', 'unknown', 'template'
        ]
    for k, v in formats.items():
        if language.split(';')[0] in k and language not in nil_reasons:
            unique_transfer.append(v)
        elif language in nil_reasons:
            unique_transfer.append(v)
    return unique_transfer
