```
# code block
class Solution(object):
def removeDuplicates(self, nums):
"""
:type nums: List[int]
:rtype: int
"""
if nums == []:
return 0
len_nums = len(nums)
indexs=[]
for i in range(len_nums-1):
for j in range(i+1, len_nums, 1):
if nums[i] == nums[j]:
indexs.append(j)
nums = [v for i, v in enumerate(nums) if i not in indexs]
len_n = len(nums)
print(nums)
return len_n
a = [1, 2, 3, 1, 2]
s = Solution()
s.removeDuplicates(a)
```