code: def postprocess_item(self, item: np_dict_type) -> np_dict_type:
      item[INPUT_KEY] = item[INPUT_KEY].ravel()
      return item
  
imports: from cftool.types import np_dict_type
  from ...schema import IRuntimeDataBlock
  from ...constants import INPUT_KEY
label_desc: Use image node_id 1 for calling the FlattenBlock obj's underlying member method code with example usage: obj.postprocess_item(item) and returns: item