input: Write a function to create a BPMN diagram for the 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". The function should take no arguments and return None.
  assert create_bpmn_diagram()==None
  assert create_bpmn_diagram()==None
  assert create_bpmn_diagram()==None
  assert create_bpmn_diagram()==None
  assert create_bpmn_diagram()==None
output: 
  def create_bpmn_diagram():
      import bpmn_pgv as bpmn
      g = bpmn.BPMN()
      
      # Create clusters
      se_cluster = g.add_cluster("Secretaría Ejecutiva")
      pres_cluster = g.add_cluster("Presidencia")
      pa_cluster = g.add_cluster("Presupuesto/Administración")
      
      # Add tasks to clusters
      se_task1 = g.add_task("Task 1", cluster=se_cluster)
      se_task2 = g.add_task("Task 2", cluster=se_cluster)
      pres_task1 = g.add_task("Task 3", cluster=pres_cluster)
      pres_task2 = g.add_task("Task 4", cluster=pres_cluster)
      pa_task1 = g.add_task("Task 5", cluster=pa_cluster)
      pa_task2 = g.add_task("Task 6", cluster=pa_cluster)
      
      # Add edges within clusters
      g.add_edge(se_task1, se_task2)
      g.add_edge(pres_task1, pres_task2)
      g.add_edge(pa_task1, pa_task2)
      
      # Add nodes for SIGEFOMDES Administración and SISAC
      sigefomdes = g.add_task("SIGEFOMDES Administración")
      sisac = g.add_task("SISAC")
      
      # Connect nodes to clusters with dashed edges
      g.add_edge(sigefomdes, se_task1, style="dashed")
      g.add_edge(sisac, pres_task1, style="dashed")
      
      # Save the diagram
      g.save("proc4.png", "proc4.dot")
      
      return None
  