code: def append(self, v):
      if self.length < self.maxlen:
          # We have space, simply increase the length.
          self.length += 1
      elif self.length == self.maxlen:
          # No space, "remove" the first item.
          self.start = (self.start + 1) % self.maxlen
      else:
          # This should never happen.
          raise RuntimeError()
      self.data[(self.start + self.length - 1) % self.maxlen] = v
  
imports: from __future__ import absolute_import
  from collections import deque, namedtuple
  import warnings
  import random
  import numpy
label_desc: Use image node_id 4 for calling the RingBuffer obj's underlying member method code with example usage: obj.append(v) without return types