How to convert Nonetype to integer?

This value exists in the list.

list = ['4', '4', '4', '1,119', '1,119', '1,119']

i try convert Nonetype to int.

list = ['4', '4', '4', '1,119', '1,119', '1,119']

for i in list :
     a = [int(x.replace(',', '')) for x in list]

print(set(list))

TypeError: 'NoneType' object is not iterable

i want output

list = [4,1119]