code: def isfile(f):
      """
      Check file object in python 2.7 & 3.x.
  
      :param f: input object
      :type f: file object
      :return: file type check as boolean
      """
      return (
          isinstance(f, file)
          if sys.version_info[0] == 2
          else hasattr(f, "read")
      )
  
imports: from __future__ import division
  import sys
  import math
  import numpy
  import re
  from .pycm_param import *
  from .pycm_error import pycmMatrixError
  from warnings import warn
  from functools import wraps
label_desc: Use image node_id 9 for calling a global function with example usage: isfile(f) and returns: unknown