code: def export_definitions_element():
          
          root = eTree.Element(consts.Consts.definitions)
          root.set("xmlns", "http://www.omg.org/spec/BPMN/20100524/MODEL")
          root.set("xmlns:bpmndi", "http://www.omg.org/spec/BPMN/20100524/DI")
          root.set("xmlns:omgdc", "http://www.omg.org/spec/DD/20100524/DC")
          root.set("xmlns:omgdi", "http://www.omg.org/spec/DD/20100524/DI")
          root.set("xmlns:xsi", "http://www.w3.org/2001/XMLSchema-instance")
          root.set("targetNamespace", "http://www.signavio.com/bpmn20")
          root.set("typeLanguage", "http://www.w3.org/2001/XMLSchema")
          root.set("expressionLanguage", "http://www.w3.org/1999/XPath")
          root.set("xmlns:xsd", "http://www.w3.org/2001/XMLSchema")
  
          return root
docs: Creates root element ('definitions') for exported BPMN XML file.
  
          :return: definitions XML element.