input: Write a function to create a BPMN diagram for FOMDES process 1 using Python and the bpmn_pgv library. 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, save the diagram as a PNG file named "proc4.png" and a DOT file named "proc4.dot".
  assert create_bpmn_diagram()=="proc4.png generated successfully"
output: 
  def create_bpmn_diagram():
      import bpmn_pgv as bpmn
      from graphviz import Digraph
  
      g = Digraph('G', filename='proc4.dot')
  
      # Secretaría Ejecutiva cluster
      with g.subgraph(name='cluster_Secretaría_Ejecutiva') as c:
          c.attr(label='Secretaría Ejecutiva')
          c.node('Task1', 'Task 1')
          c.node('Task2', 'Task 2')
          c.edge('Task1', 'Task2')
  
      # Presidencia cluster
      with g.subgraph(name='cluster_Presidencia') as c:
          c.attr(label='Presidencia')
          c.node('Task3', 'Task 3')
          c.node('Task4', 'Task 4')
          c.edge('Task3', 'Task4')
  
      # Presupuesto/Administración cluster
      with g.subgraph(name='cluster_Presupuesto_Administración') as c:
          c.attr(label='Presupuesto/Administración')
          c.node('Task5', 'Task 5')
          c.node('Task6', 'Task 6')
          c.edge('Task5', 'Task6')
  
      # Nodes outside clusters
      g.node('SIGEFOMDES_Administración', 'SIGEFOMDES Administración')
      g.node('SISAC', 'SISAC')
  
      # Dashed edges
      g.edge('SIGEFOMDES_Administración', 'Task1', style='dashed')
      g.edge('SISAC', 'Task3', style='dashed')
  
      # Save the diagram
      g.render(filename='proc4', format='png')
  
      return "proc4.png generated successfully"
  