写一个函数求出已知队列数值最大值

a = [1.2,26,-3,-1,684,'sfggh',"896",412,'asdf']
k = 'x'
for v in a:
    #if(isinstance(v,int) or isinstance(v,float)):
    try:
        v1 = float(v)
        if(k == 'x'):
            k = v1
        else:
            if(v1 > k):
                k = v1
    except Exception as err:
        print('错误信息:',err)
if(k == 'x'):
    print('找不到最大值')
else:
    print('最大值为',k)

#找最大值
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