code: def import_collaboration_element(diagram_graph, collaboration_element, collaboration_dict):
          
          collaboration_dict[consts.Consts.id] = collaboration_element.getAttribute(consts.Consts.id)
          collaboration_dict[consts.Consts.participants] = {}
          participants_dict = collaboration_dict[consts.Consts.participants]
          collaboration_dict[consts.Consts.message_flows] = {}
          message_flows_dict = collaboration_dict[consts.Consts.message_flows]
  
          for element in utils.BpmnImportUtils.iterate_elements(collaboration_element):
              if element.nodeType != element.TEXT_NODE:
                  tag_name = utils.BpmnImportUtils.remove_namespace_from_tag_name(element.tagName)
                  if tag_name == consts.Consts.participant:
                      BpmnDiagramGraphImport.import_participant_element(diagram_graph, participants_dict, element)
                  elif tag_name == consts.Consts.message_flow:
                      BpmnDiagramGraphImport.import_message_flow_to_graph(diagram_graph, message_flows_dict, element)
docs: Method that imports information from 'collaboration' element.
  
          :param diagram_graph: NetworkX graph representing a BPMN process diagram,
          :param collaboration_element: XML doument element,
          :param collaboration_dict: dictionary, that consist all information imported from 'collaboration' element.
              Includes three key-value pairs - 'id' which keeps ID of collaboration element, 'participants' that keeps
              information about 'participant' elements and 'message_flows' that keeps information about message flows.