def convert_coco_to_voc(label):
    """Converts COCO class name to VOC class name, if possible.

    COCO classes are a superset of VOC classes, but
    some classes have different names (e.g. airplane
    in COCO is aeroplane in VOC). This function gets
    COCO label and converts it to VOC label,
    if conversion is needed.

    Args:
        label (str): COCO label
    Returns:
        str: VOC label corresponding to given label if such exists,
            otherwise returns original label
    """
    COCO_VOC_DICT = {
        'airplane': 'aeroplane',
        'motorcycle': 'motorbike',
        'dining table': 'diningtable',
        'potted plant': 'pottedplant',
        'couch': 'sofa',
        'tv': 'tvmonitor'
    }
    if label in COCO_VOC_DICT:
        return COCO_VOC_DICT[label]
    else:
        return label