input: Write a function called `create_bpmn_diagram` that generates a BPMN diagram for the FOMDES process 1 using the bpmn_pgv library in Python. The function 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, the function should save the diagram as a PNG file named "proc4.png" and a DOT file named "proc4.dot".
  
  assert create_bpmn_diagram() is None
output: def create_bpmn_diagram():
      import bpmn_pgv as bpmn
      G = bpmn.BPMNGraph()
  
      # Secretaría Ejecutiva cluster
      with G.as_default():
          with G.cluster(name='Secretaría Ejecutiva'):
              G.node('SE1', 'Task 1')
              G.node('SE2', 'Task 2')
              G.edge('SE1', 'SE2')
  
      # Presidencia cluster
      with G.as_default():
          with G.cluster(name='Presidencia'):
              G.node('P1', 'Task 3')
              G.node('P2', 'Task 4')
              G.edge('P1', 'P2')
  
      # Presupuesto/Administración cluster
      with G.as_default():
          with G.cluster(name='Presupuesto/Administración'):
              G.node('PA1', 'Task 5')
              G.node('PA2', 'Task 6')
              G.edge('PA1', 'PA2')
  
      # Nodes outside clusters
      G.node('SIGEFOMDES', 'SIGEFOMDES Administración')
      G.node('SISAC', 'SISAC')
  
      # Dashed edges to connect nodes to clusters
      G.edge('SIGEFOMDES', 'SE1', style='dashed')
      G.edge('SISAC', 'P1', style='dashed')
  
      # Save the diagram
      G.draw('proc4.png', prog='dot')
      G.write('proc4.dot')