Update emails_mert_can_fidan.py

I make it string validation with regex instead of simply check @ character.

Author: usrmertc

Week05/emails_mert_can_fidan.py

@@ -1,3 +1,5 @@
+import re
+
 class Emails(list):
     def __init__(self, data: [str]) -> None:
         self.data = list(set(data))
@@ -10,8 +12,18 @@ def __str__(self):
         return f"Emails: {self.data}"
 
     def validate(self, data: [str]) -> None:
+        # Validate email addresses according to the pattern used by Gmail.
+        # The local part (before the @) can contain:
+        # - Alphanumeric characters
+        # - Periods (.) but not consecutively or at the start/end
+        # The domain part (after the @) can contain:
+        # - Alphanumeric characters
+        # - Periods (.) followed by at least two alphabetic characters
+        # This pattern also supports subdomains.
+        regex_pattern = r"^[A-Za-z0-9]+(?:[.][A-Za-z0-9]+)*@[A-Za-z0-9]+(?:\.[A-Za-z]{2,}){1,2}$"
+
         for email in data:
             if isinstance(email, int):
                 raise ValueError("Only string values accepted!")
-            if "@" not in email:
+            if not re.match(regex_pattern, email):
                 raise ValueError("This is not an email adress!")