code: def upgrade():
      op.add_column(
          "dbs",
          sa.Column("allow_run_async", sa.Boolean(), nullable=True),
      )
      op.add_column(
          "dbs",
          sa.Column("allow_run_sync", sa.Boolean(), nullable=True),
      )
  
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