docstr: Return number of observations
  
  # Returns
      Number of observations
docstr_tok: ["Return","number","of","observations","#","Returns","Number","of","observations"]
code: def nb_entries(self):
      """Return number of observations
  
      # Returns
          Number of observations
      """
      return len(self.observations)
  
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 SequentialMemory obj's underlying member method code with example usage: obj.nb_entries() and returns: len