new_contents: from UM.Qt.ListModel import ListModel
  
  from PyQt5.QtCore import Qt
  
  class MachinesModel(ListModel):
      NameRole = Qt.UserRole + 1
  
      def __init__(self):
          super().__init__()
  
          self.addRoleName(self.NameRole, 'name')
  
          for i in range(10):
              self.appendItem({'name': "Ultimaker {0}".format(i)})
  
  
subject: Add a MachinesModel class that is currently just a list of strings