code: def run_migrations_online() -> None:
      """Run migrations in 'online' mode.
  
      In this scenario we need to create an Engine
      and associate a connection with the context.
  
      """
  
      # this callback is used to prevent an auto-migration from being generated
      # when there are no changes to the schema
      # reference: https://alembic.sqlalchemy.org/en/latest/cookbook.html
      def process_revision_directives(  # pylint: disable=redefined-outer-name, unused-argument
          context: MigrationContext,
          revision: str,
          directives: list[MigrationScript],
      ) -> None:
          if getattr(config.cmd_opts, "autogenerate", False):
              script = directives[0]
              if script.upgrade_ops.is_empty():
                  directives[:] = []
                  logger.info("No changes in schema detected.")
  
      engine = engine_from_config(
          config.get_section(config.config_ini_section),
          prefix="sqlalchemy.",
          poolclass=pool.NullPool,
      )
  
      connection = engine.connect()
      kwargs = {}
      if engine.name in ("sqlite", "mysql"):
          kwargs = {
              "transaction_per_migration": True,
              "transactional_ddl": True,
          }
      if configure_args := current_app.extensions[
          "migrate"
      ].configure_args:
          kwargs.update(configure_args)
  
      context.configure(
          connection=connection,
          target_metadata=target_metadata,
          # compare_type=True,
          process_revision_directives=process_revision_directives,
          **kwargs,
      )
  
      try:
          with context.begin_transaction():
              context.run_migrations()
      finally:
          connection.close()
  
file_path: superset/superset/migrations/env.py
imports: import logging
  import urllib.parse
  from logging.config import fileConfig
  from alembic import context
  from alembic.operations.ops import MigrationScript
  from alembic.runtime.migration import MigrationContext
  from flask import current_app
  from flask_appbuilder import Base
  from sqlalchemy import engine_from_config, pool
label_desc: Use image node_id 2 for calling a global function with example usage: run_migrations_online() without return types