Leetcode 929. Unique Email Addresses

class Solution(object):
    def numUniqueEmails(self, emails):
        """
        :type emails: List[str]
        :rtype: int
        """
        ans = []
        for i, em in enumerate(emails):

            add, at = -1, -1
            size = len(em)
            for j in range(size):
                if em[j] == ‘@‘:
                    at = j
                    break
                if em[j] == ‘+‘:
                    if add == -1:
                        add = j
            if add != -1:
                ans.append(em[:add].replace(‘.‘,‘‘) + em[at:])
            else:
                ans.append(em[:at].replace(‘.‘,‘‘)+em[at:])

        ans = set(ans)
        return len(ans)