Unexpected formatting of time stamp when writing to a new file?`

Using 7.9.4.

Have a task where I am supposed to send two CSV files to to similar but different location. One file the timestamps are normal human readable and the other is isoformat.

I convert the existing file with normal time stamps to iso format with the following function. I had an issue where this itself was not actually writing the iso style format (hence all the print debugs) and I realized csv.writer was autoformatting the datetimes until I put a str around it.

def convertFileToIsoFormat(read_filePath, write_filePath):
	This file takes an already created data text file, reads through it and
	converts the time stamp columns to isoformat.
		read_filePath: str, file to read
		write_filePath: str, where to put the new file
		None, or raises error
	with open(read_filePath) as csvfile:
		with open(write_filePath, 'wb') as newcsv:
			reader = csv.reader(csvfile)
			writer = csv.writer(newcsv)#lineterminator='\n'
			for row in reader:
				modifiedRow = row
				for column in TIMESTAMP_COLUMNS:
					print column
					print row[column]
					modifiedRow[column] = str(datetime.datetime.strptime(modifiedRow[column],'%m/%d/%Y %H:%M:%S %p').isoformat())
					print modifiedRow[column]
				print 'writing row %s'%(str(modifiedRow))

The above works for converting the entire file.

Now, I have to split the file into 3 MB chunks. This is where my iso formatted datetimes are getting converted back into human readable timestamps but I just want to keep them in iso format. Here is my current function -

def splitFile(fileToProcess, folderToStoreTo):
	Takes a data file and splits it into <3MB chunks
		fileToProcess: str, file path to split into chunks
		destDir: str, destination directory to put split files into
		filePaths: list of strings of filepaths of texts that were made
	LOGGER.info("fileToProccess %s folderToStore %s"%(str(fileToProcess), str(folderToStoreTo)))
	currentLineCount = 0
	readFileName = fileToProcess.split('\\')[-1]
	filesMade = 1
	filePaths = []
	with open(fileToProcess) as f:
		line = f.readline()	
		while line:			
			filename = readFileName.split('.')[0]+'-%i'%(filesMade)+'.txt'
			fullPath = folderToStoreTo + "\\" + filename
			for l in range(0,maxLinesPerFile):
#				print line
				writeData = "%s%s"%(line, os.linesep)
				system.file.writeFile(fullPath, writeData, 1)
				line = f.readline()
				currentLineCount += 0
				if not line:
			filesMade += 1
		print type(line), line, str(line)
	return filePaths

I don't know why this is reading things as an iso and reformatting them back to a regular timestamp. You can probably recreate this if you use my second function and feed it a csv file that has iso formatted tiemstmaps. I have no idea what is going wrong here. The only thing I can thing is my with open(fileToProcess) is doing something behind the scenes in formatting the date or system.file.writeFile is doing somethign in processing the dates. I've tried changing my with open(fileToPrcess) as f: and I tried changing writeData = "%s%s"%(line, os.linesep) since a well placed str() fixed my previous issue but neither worked.

I am out of ideas. Something is obviously going on the background but I don't know where so I am having trouble figuring out how to stop it. Any insight is appreciated.

As usual this was a programming error, I was feeding in the original file into my splitFile function instead of the newly converted ISO file. Nothing to see here folks.