code: def upgrade():
      op.create_table(
          "dashboard_roles",
          sa.Column("id", sa.Integer(), nullable=False),
          sa.Column("role_id", sa.Integer(), nullable=False),
          sa.Column("dashboard_id", sa.Integer(), nullable=True),
          sa.ForeignKeyConstraint(["dashboard_id"], ["dashboards.id"]),
          sa.ForeignKeyConstraint(["role_id"], ["ab_role.id"]),
          sa.PrimaryKeyConstraint("id"),
      )
  
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