问如何修复此代码中的可被0整除错误

EN

 for key in results_dic:

    # match (if dog then breed match)
    if results_dic[key][2] == 1:

        # isa dog (pet label) & breed match
        if results_dic[key][3] == 1:
            n_pet_dog += 1

            # isa dog (classifier label) & breed match
            if results_dic[key][4] == 1:
                n_class_cdog += 1
                n_match_breed += 1

        # NOT dog (pet_label)
        else:

            # NOT dog (classifier label)
            if results_dic[key][4] == 0:
                n_class_cnotd += 1

    # NOT - match (not a breed match if a dog)
    else:

        # NOT - match
        # isa dog (pet label) 
        if results_dic[key][3] == 1:
            n_pet_dog += 1

            # isa dog (classifier label)
            if results_dic[key][4] == 1:
                n_class_cdog += 1

        # NOT dog (pet_label)
        else:

            # NOT dog (classifier label)
            if results_dic[key][4] == 0:
                n_class_cnotd += 1


# calculates statistics based upon counters from above
n_pet_notd = n_images - n_pet_dog
pct_corr_dog = ( n_class_cdog / n_pet_dog )*100
pct_corr_notdog = ( n_class_cnotd / n_pet_notd )*100
pct_corr_breed = ( n_match_breed / n_pet_dog )*100