diff --git a/migrations/versions/2a3b4c5d6e7f_add_username_field.py b/migrations/versions/2a3b4c5d6e7f_add_username_field.py
index bc46334..0bf25ab 100644
--- a/migrations/versions/2a3b4c5d6e7f_add_username_field.py
+++ b/migrations/versions/2a3b4c5d6e7f_add_username_field.py
@@ -20,7 +20,7 @@ def upgrade() -> None:
     # Add username column to user table
     with op.batch_alter_table('user') as batch_op:
         batch_op.add_column(sa.Column('username', sa.String(), nullable=True))
-        batch_op.create_index(op.f('ix_user_username'), 'username', unique=True)
+        batch_op.create_index('ix_user_username', ['username'], unique=True)
         
     # For existing users, initialize username from email
     # This is just SQL template code - in a real migration with existing data,
@@ -38,5 +38,5 @@ def upgrade() -> None:
 def downgrade() -> None:
     # Remove username column from user table
     with op.batch_alter_table('user') as batch_op:
-        batch_op.drop_index(op.f('ix_user_username'))
+        batch_op.drop_index('ix_user_username')
         batch_op.drop_column('username')
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