code: def upgrade():
      with op.batch_alter_table(
          SqlModelVersion.__tablename__
      ) as batch_op:
          batch_op.alter_column(
              "run_id", nullable=True, existing_type=sa.VARCHAR(32)
          )
  
imports: from alembic import op
  import sqlalchemy
  from mlflow.store.model_registry.dbmodels.models import SqlModelVersion
label_desc: Use image node_id 1 for calling a global function with example usage: upgrade() without return types