input: Write a function to create a BPMN diagram for FOMDES process 1 using the bpmn_pgv library in Python. 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"
  assert read_file_as_string("proc4.dot") is not None
output: def create_bpmn_diagram():
      import bpmn_pgv as bpmn
      import graphviz as gv
  
      # Create a new BPMN diagram
      proc4 = bpmn.BPMN()
  
      # Create clusters for each department
      secretaria_ejecutiva = proc4.add_cluster(id="Secretaría Ejecutiva", name="Secretaría Ejecutiva")
      presidencia = proc4.add_cluster(id="Presidencia", name="Presidencia")
      presupuesto_administracion = proc4.add_cluster(id="Presupuesto/Administración", name="Presupuesto/Administración")
  
      # Add tasks to each cluster
      secretaria_ejecutiva.add_task(id="Task1", name="Task 1")
      secretaria_ejecutiva.add_task(id="Task2", name="Task 2")
      presidencia.add_task(id="Task3", name="Task 3")
      presidencia.add_task(id="Task4", name="Task 4")
      presupuesto_administracion.add_task(id="Task5", name="Task 5")
      presupuesto_administracion.add_task(id="Task6", name="Task 6")
  
      # Add nodes for SIGEFOMDES Administración and SISAC
      sigefomdes = proc4.add_node(id="SIGEFOMDES Administración", name="SIGEFOMDES Administración")
      sisac = proc4.add_node(id="SISAC", name="SISAC")
  
      # Connect nodes to clusters with dashed edges
      proc4.add_edge(sigefomdes, secretaria_ejecutiva.get_task("Task1"), style="dashed")
      proc4.add_edge(sisac, presidencia.get_task("Task3"), style="dashed")
  
      # Save the diagram as a PNG and DOT file
      proc4.draw("proc4.png")
      proc4.write("proc4.dot")
  
      return "proc4.png"