code: def upgrade():
      """Apply Add has_import_errors column to DagModel"""
      op.add_column(
          "dag",
          sa.Column(
              "has_import_errors", sa.Boolean(), server_default="0"
          ),
      )
  
imports: from __future__ import annotations
  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