[Python] File Handler created using ctypes is invalid

I was trying to create a new file using ctypes in python. The file gets created and I am able to write in to it. The problem starts when I try to read from this file. It gives me an invalid file handle error. Anyone might know why this is the case.

The following is the code I used:

from ctypes import *

def CreateFile(file_name='',data=''):

file_handler=windll.Kernel32.CreateFileA(file_name,0x10000000,0,None,4,0x80,None)

pointer_to_written_data=c_int(0)
windll.Kernel32.WriteFile(file_handler,data,len(data),byref(pointer_to_written_data),None)
windll.Kernel32.CloseHandle(file_handler)
return

def ReadAFile(file_name=''):

file_handler=windll.Kernel32.CreateFileA(file_name,0x10000000,0,None,4,0x80,None)
data=create_string_buffer(4096)
pointer_to_read_data=c_int(0)
if(windll.Kernel32.ReadFile(file_handler,byref(data),1024,byref(pointer_to_read_data),None)==0):
print "Failed"
print windll.Kernel32.GetLastError()
windll.Kernel32.CloseHandle(file_handler)
print data.value
return

CreateFile("sample.txt","This is a test file!!")
ReadAFile("sample.txt")

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