input: Write a function to create a BPMN diagram for FOMDES process 1 using Python and the bpmn_pgv library. The function should generate the diagram with clusters for Secretaría Ejecutiva, Presidencia, and Presupuesto/Administración, including specific tasks and edges within each cluster. Additionally, it should 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
      from graphviz import Digraph
  
      g = Digraph('G', filename='proc4.dot')
      g.attr(rankdir='LR')
  
      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')
  
      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')
  
      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')
  
      g.node('SIGEFOMDES_Administración', 'SIGEFOMDES Administración')
      g.node('SISAC', 'SISAC')
  
      g.edge('SIGEFOMDES_Administración', 'Task1', style='dashed')
      g.edge('SISAC', 'Task3', style='dashed')
  
      g.render('proc4', format='png', view=False)
      return None