input: Write a function to create a BPMN diagram for FOMDES process 1 using Python and the bpmn_pgv library. The diagram should include clusters for Secretaría Ejecutiva, Presidencia, and Presupuesto/Administración, with specific tasks and edges defined within each cluster. Additionally, include nodes for SIGEFOMDES Administración and SISAC, and connect them to the appropriate clusters using dashed edges. Finally, save the diagram as a PNG file named "proc4.png" and a DOT file named "proc4.dot".
  
  assert create_bpmn_diagram() == "proc4.png", "proc4.dot"
  assert create_bpmn_diagram() is not None
output: def create_bpmn_diagram():
      import bpmn_pgv as bpmn
  
      g = bpmn.BPMNGraph()
  
      # Clusters
      g.add_cluster("Secretaría Ejecutiva", "Secretaría Ejecutiva")
      g.add_cluster("Presidencia", "Presidencia")
      g.add_cluster("Presupuesto/Administración", "Presupuesto/Administración")
  
      # Tasks within clusters
      g.add_task("Secretaría Ejecutiva", "Task1", "Task1")
      g.add_task("Secretaría Ejecutiva", "Task2", "Task2")
      g.add_task("Presidencia", "Task3", "Task3")
      g.add_task("Presidencia", "Task4", "Task4")
      g.add_task("Presupuesto/Administración", "Task5", "Task5")
      g.add_task("Presupuesto/Administración", "Task6", "Task6")
  
      # Edges within clusters
      g.add_edge("Task1", "Task2")
      g.add_edge("Task3", "Task4")
      g.add_edge("Task5", "Task6")
  
      # Nodes
      g.add_node("SIGEFOMDES Administración", "SIGEFOMDES Administración")
      g.add_node("SISAC", "SISAC")
  
      # Dashed edges
      g.add_edge("SIGEFOMDES Administración", "Task1", style="dashed")
      g.add_edge("SISAC", "Task3", style="dashed")
  
      # Save diagram
      g.write_png("proc4.png")
      g.write_dot("proc4.dot")
  
      return "proc4.png", "proc4.dot"