code: def upgrade() -> None:
      # ### commands auto generated by Alembic - please adjust! ###
      op.add_column(
          "datasets",
          sa.Column("last_activity_at", sa.DateTime(), nullable=True),
      )
      op.execute("UPDATE datasets SET last_activity_at = updated_at")
      with op.batch_alter_table("datasets") as batch_op:
          batch_op.alter_column("last_activity_at", nullable=False)
  
imports: import sqlalchemy
  from alembic import op
label_desc: Use image node_id 1 for calling a global function with example usage: upgrade() without return types