code: def _flatten(xs):
      if _is_array(xs):
          return [xs]
  
      o = []
      for x in xs:
          if _is_array(x):
              o.append(x)
          else:
              o.extend(_flatten(x))
      return o
  
file_path: chainer/onnx_chainer/replace_func.py
imports: import inspect
  import chainer
label_desc: Use image node_id 6 for calling a global function with example usage: _flatten(xs) and returns: o, list