def _compare_blocks(block_a, block_b):
    logger.debug('_compare_blocks(%s, %s)', block_a, block_b)
    if block_a[0].isdigit():
        _trim_zeros(block_a, block_b)
        if len(block_a) != len(block_b):
            logger.debug('block lengths are not equal')
            return a_newer if len(block_a) > len(block_b) else b_newer
    if block_a == block_b:
        logger.debug('blocks are equal')
        return a_eq_b
    else:
        logger.debug('blocks are not equal')
        return a_newer if block_a > block_b else b_newer