class_docstr: Helper Abstract Base Class which defines all methods that
  a StorageBackend must implement.
class_docstr_tok: ["Helper","Abstract","Base","Class","which","defines","all","methods","that","a","StorageBackend","must","implement","."]
docstr: Opens an item on the store and return a file-like object.
  
  This method is private and only used by the StoreBackendMixin object.
  
  Parameters
  ----------
  f: a file-like object
      The file-like object where an item is stored and retrieved
  mode: string, optional
      the mode in which the file-like object is opened allowed valued are
      'rb', 'wb'
  
  Returns
  -------
  a file-like object
docstr_tok: ["Opens","an","item","on","the","store","and","return","a","file-like","object",".","This","method","is","private","and","only","used","by","the","StoreBackendMixin","object",".","Parameters","--","--","--","--","--","f",":","a","file-like","object","The","file-like","object","where","an","item","is","stored","and","retrieved","mode",":","string",",","optional","the","mode","in","which","the","file-like","object","is","opened","allowed","valued","are","'rb","'",",","'wb'","Returns","--","--","--","-","a","file-like","object"]
code: def _open_item(self, f, mode):
      """Opens an item on the store and return a file-like object.
  
      This method is private and only used by the StoreBackendMixin object.
  
      Parameters
      ----------
      f: a file-like object
          The file-like object where an item is stored and retrieved
      mode: string, optional
          the mode in which the file-like object is opened allowed valued are
          'rb', 'wb'
  
      Returns
      -------
      a file-like object
      """
  
imports: from pickle import PicklingError
  import re
  import os
  import os.path
  import datetime
  import json
  import shutil
  import warnings
  import collections
  import operator
  import threading
  from abc import ABCMeta, abstractmethod
  from .backports import concurrency_safe_rename
  from .disk import mkdirp, memstr_to_bytes, rm_subdirs
  from .None import numpy_pickle
label_desc: Use image node_id 1 for calling the StoreBackendBase obj's underlying member method code with example usage: obj._open_item(f, mode) without return types