leetcode Remove Duplicates from Sorted Array python

class Solution(object):
    def removeDuplicates(self,nums):
    if len(nums) <= 0:
        return 0

    j=0
    for i in range(0,len(nums)):
        if nums[i] != nums[j]:
        print 'i j is ',i,j
        nums[i],nums[j+1] = nums[j+1],nums[i]
        j=j+1
    return j+1