class_docstr: Abstract class for data iterators.
  
  For serialization, any data iterator should inherit from this class
docstr: Return the number of minibatches in this dataset.
docstr_tok: ["Return","the","number","of","minibatches","in","this","dataset","."]
code: def nbatches(self):
      """
      Return the number of minibatches in this dataset.
      """
      raise NotImplemented()
  
file_path: neon/neon/data/dataiterator.py
imports: from builtins import zip
  import numpy
  from neon import NervanaObject
label_desc: Use image node_id 2 for calling the NervanaDataIterator obj's underlying member method code with example usage: obj.nbatches() without return types