检查列表中的元素时出现“TypeError:类型为'int'的参数不可迭代”

我在Spyder上使用Python 3.7,并有以下代码

def NailingPlanks(A,B,C):
    numInervals = len(A)
    maxNails = len(C)
    
    intervals = []
    covered = [0]*numInervals
    
    for i in range(numInervals):
        interval = []
        for j in range(A[i],B[i]+1): interval.append(j)
        intervals.append(interval)
        
    nails = []
    nailUsed = [False] * maxNails
    print('covered = ', covered)
    while (0 in covered):
        MaxCovered = 0
        for i in range(maxNails):
            if not nailUsed[i]:
                nail = C[i]
                cnt = 0
                for j in range(numInervals):
                    if covered[j]==0 and nail in intervals[j]: cnt += 1
                if cnt>MaxCovered:
                    MaxCovered = cnt
                    maxIndex = i
        nails.append(maxIndex)
        nailUsed[maxIndex] = True
        for j in range(numInervals):
            if nail in intervals[j]: covered=1
            
    print('nails=', nails)
    return len(nails)

当它运行时,我得到以下输出

Traceback (most recent call last):

  File "<ipython-input-492-8fb88643c6e1>", line 1, in <module>
    NailingPlanks(A,B,C)

File "<ipython-input-491-4c2e538033de>", line 16, in NailingPlanks
while (0 in covered):

TypeError: argument of type 'int' is not iterable

我在航站楼收到以下信息

not (0 in covered)
Out[494]: False