Directory Listing with size (no sub folders) via Python 15

PS E:\> python getDirSize06.py
running on dir "."
Traceback (most recent call last):
  File "getDirSize06.py", line 31, in <module>
    listContents();
  File "getDirSize06.py", line 23, in listContents
    f.write(str(c.encode('utf8')))
TypeError: a bytes-like object is required, not 'str'
PS E:\>