def maximum(lista):
max = float('-inf')
for item in lista:
try:
valor = int(item)
if valor > max:
max = valor
except:
pass
return max
print(maximum(['4', '07', '08', '2017', '364', '355673087875675']))
print(maximum(['4', '07', '08', '355673087875675', 'a', '2017']))
#https://pt.stackoverflow.com/q/257905/101
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