def update_fields(fields)
      attributes[:id]      = fields['id'] || attributes[:id]
      attributes[:state]   = fields['state'] || attributes[:state]
      attributes[:item_id] = fields['idCheckItem'] || attributes[:item_id]
      self
    end
def update_fields(fields)
      attributes[:id]      = fields['id'] || attributes[:id]
      attributes[:state]   = fields['state'] || attributes[:state]
      attributes[:item_id] = fields['idCheckItem'] || attributes[:item_id]
      self
    end
Update the fields of an item state.

 Supply a hash of string keyed data retrieved from the Trello API representing
 an item state.