docstr: Numerical variable store backed by NumPy.savez/load.
  
   If `archive` is specified, then `root_path` refers to the filename
  inside the archive.
  
  If `archive` is not specified, then `root_path` refers to the path of
  the npz file on disk.
docstr_tok: ["Numerical","variable","store","backed","by","NumPy.savez\/load",".","If","`","archive","`","is","specified",",","then","`","root_path","`","refers","to","the","filename","inside","the","archive",".","If","`","archive","`","is","not","specified",",","then","`","root_path","`","refers","to","the","path","of","the","npz","file","on","disk","."]
code: def __init__(self, root_path, archive=None, mode="r"):
      """Numerical variable store backed by NumPy.savez/load.
  
       If `archive` is specified, then `root_path` refers to the filename
      inside the archive.
  
      If `archive` is not specified, then `root_path` refers to the path of
      the npz file on disk.
      """
      self.root_path = root_path
      self.mode = mode
      self.archive = archive
      if mode == "w":
          self.contents = {}
      else:
          if self.archive:
              self.f = archive.open(root_path, mode="r")
          else:
              self.f = open(root_path, mode="rb")
          self.contents = np.load(self.f, allow_pickle=True)
  
imports: import datetime
  import io
  import json
  import tempfile
  import warnings
  import zipfile
  import numpy
  from keras.backend.common import global_state
  from keras.layers.layer import Layer
  from keras.losses.loss import Loss
  from keras.metrics.metric import Metric
  from keras.optimizers.optimizer import Optimizer
  from keras.saving.serialization_lib import ObjectSharingScope
  from keras.saving.serialization_lib import deserialize_keras_object
  from keras.saving.serialization_lib import serialize_keras_object
  from keras.trainers.compile_utils import CompileMetrics
  from keras.utils import file_utils
  from keras.utils import naming
  from keras.version import __version__
label_desc: Use image node_id 1 to create a new NpzIOStore object  with example: obj = NpzIOStore(root_path, archive, mode)