code: def load_diagram_from_csv(filepath, bpmn_diagram):
          
          sequence_flows = bpmn_diagram.sequence_flows
          process_elements_dict = bpmn_diagram.process_elements
          diagram_attributes = bpmn_diagram.diagram_attributes
          plane_attributes = bpmn_diagram.plane_attributes
  
          process_dict = BpmnDiagramGraphCSVImport.import_csv_file_as_dict(filepath)
  
          BpmnDiagramGraphCSVImport.populate_diagram_elements_dict(diagram_attributes)
          BpmnDiagramGraphCSVImport.populate_process_elements_dict(process_elements_dict, process_dict)
          BpmnDiagramGraphCSVImport.populate_plane_elements_dict(plane_attributes)
  
          BpmnDiagramGraphCSVImport.import_nodes(process_dict, bpmn_diagram, sequence_flows)
          BpmnDiagramGraphCSVImport.representation_adjustment(process_dict, bpmn_diagram, sequence_flows)
docs: Reads an CSV file from given filepath and maps it into inner representation of BPMN diagram.
          Returns an instance of BPMNDiagramGraph class.
  
          :param filepath: string with output filepath,
          :param bpmn_diagram: an instance of BpmnDiagramGraph class.