code: def get_values(self):
          
          elements_selected = {}
          for index in range(self.tree_loaded_model.rowCount()):
              element_name = str(self.tree_loaded_model.item(index).text())
              if element_name in self.elements_old:
                  elements_selected.update({element_name: self.elements_old[element_name]})
              elif element_name in self.elements_from_file:
                  elements_selected.update({element_name: self.elements_from_file[element_name]})
  
  
          return elements_selected
docs: Returns: the selected instruments