https://leetcode.com/problems/unique-email-addresses/

unique_emails.py

class Solution:
    def numUniqueEmails(self, emails: List[str]) -> int:
        uniques = set()
        for email in emails:
            uniques.add(parse_email(email))
        return len(uniques)


def parse_email(email: str) -> str:
    first_half, second_half = email.split('@')
    no_periods = first_half.replace('.', '')
    plus_index = no_periods.find('+')
    if plus_index > 0:
        clean_first =  no_periods[:plus_index]
    else:
        clean_first = no_periods
    return f"{clean_first}@{second_half}"



import unittest
class TestSolution(unittest.TestCase):

    def test_example_one(self):
        emails = ["test.email+alex@leetcode.com","test.e.mail+bob.cathy@leetcode.com","testemail+david@lee.tcode.com"]
        results = 2

        sol_output = Solution().numUniqueEmails(emails)
        self.assertEqual(sol_output, results)

    def test_case_180(self):
        emails = ["a@leetcode.com","b@leetcode.com","c@leetcode.com"]
        results = 3

        sol_output = Solution().numUniqueEmails(emails)
        self.assertEqual(sol_output, results)