code: def export_dashboards(session: Session) -> str:
      """Returns all dashboards metadata as a json dump"""
      logger.info("Starting export")
      dashboards = session.query(Dashboard)
      dashboard_ids = set()
      for dashboard in dashboards:
          dashboard_ids.add(dashboard.id)
      data = Dashboard.export_dashboards(dashboard_ids)
      return data
  
imports: import logging
  from sqlalchemy.orm import Session
  from superset.models.dashboard import Dashboard
label_desc: Use image node_id 1 for calling a global function with example usage: export_dashboards(session) and returns: data