instance vs class attributes — and the bug ai ships every time

Last drill. Build a User class that uses both buckets correctly:

• Class attribute domain = "example.com" (a constant — same for every user).
• Instance attributes (assigned in __init__):
  • username (passed in)
  • permissions — an empty list (must be per-instance)
• Method email() returns f"{self.username}@{self.domain}".
• Method grant(perm) appends perm to self.permissions.

Two users, distinct permission lists, shared domain string.

Expected output:

maya@example.com
marcus@example.com
['read']
['read', 'write']