code: def import_task_to_graph(diagram_graph, process_id, process_attributes, task_element):
          
          BpmnDiagramGraphImport.import_activity_to_graph(diagram_graph, process_id, process_attributes, task_element)
docs: Adds to graph the new element that represents BPMN task.
          In our representation tasks have only basic attributes and elements, inherited from Activity type,
          so this method only needs to call add_flownode_to_graph.
  
          :param diagram_graph: NetworkX graph representing a BPMN process diagram,
          :param process_id: string object, representing an ID of process element,
          :param process_attributes: dictionary that holds attribute values of 'process' element, which is parent of
              imported flow node,
          :param task_element: object representing a BPMN XML 'task' element.