jaccard.py

def jaccard(box_a, box_b):
    """box_X is a tuple of the shape (x1, y1, x2, y2)."""
    side1 = max(0, min(a[2], b[2]) - max(a[0], b[0]))
    side2 = max(0, min(a[3], b[3]) - max(a[1], b[1]))
    inter = side1 * side2
    
    area_a = (a[2] - a[0]) * (a[3] - a[1])
    area_b = (b[2] - b[0]) * (b[3] - b[1])
    union = area_a + area_b - inter
    
    return inter / union


def is_valid(box_pred, box_true, threshold=0.3):
    return jaccard(box_red, box_true) >= threshold
    

Looks like

def is_valid(box_pred, box_true, threshold=0.3):
    return jaccard(box_red, box_true) >= threshold

should be

def is_valid(box_red, box_true, threshold=0.3):
    return jaccard(box_red, box_true) >= threshold

i.e. box_red instead of box_pred as the first parameter.