def find_precision_at_recall(precision, recall, recall_level=0.9):
    """ Returns the precision at a specified level of recall.

    Args:
        precision: Fraction of positive instances over detected ones.
        recall: Fraction of detected positive instance over all positive instances.
        recall_level: A float between 0 and 1.0, the level of recall to retrieve precision at.

    Returns:
        precision at the specified recall_level
    """
    
    if precision is None or recall is None:
        print('Returning 0')
        return 0.0

    for p, r in zip(precision, recall):
        if r is None or r < recall_level:
            continue
        return p

    return 0.0