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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def load_diagram_from_csv(filepath, bpmn_diagram):
 """ 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. """

        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)