code: def setnframes(self, nframes):
      if self._nframeswritten:
          raise Error(
              "cannot change parameters after starting to write"
          )
      if nframes < 0:
          raise Error("# of frames cannot be negative")
      self._nframes = nframes
  
imports: from collections import namedtuple
  import warnings
label_desc: Use image node_id 12 for calling the Au_write obj's underlying member method code with example usage: obj.setnframes(nframes) without return types