closes google#34089

Updated validations.py python script.
Fixed the behavior of validate_user function in validations.py.

Course3/Lab4/validations.py

@@ -18,6 +18,7 @@ def validate_user(username, minlen):
     # Usernames can't begin with a number
     if username[0].isnumeric():
         return False
+#Fixing the error by checking the first character:
     if username[0] == '.' or username[0] == '_':
         return False
     return True