Update parse_philly_traces.py with docstring and cleanup

"""

See raps/dataloaders/philly.py for how to download philly traces.

Run following to parse philly traces into separate files for each day:

    python /path/to/raps/scripts/parse_philly_traces.py cluster_cpu_util

    python /path/to/raps/scripts/parse_philly_traces.py cluster_gpu_util

This will parse these two files into two directories, cpu_by_day and gpu_by_day,

creating one file for each day and adding the lines for that day into the files.

"""

import os

import sys

from datetime import datetime

    output_dir = "cpu_by_day" if is_cpu else "gpu_by_day"

    os.makedirs(output_dir, exist_ok=True)

    #for i, line in enumerate(f, 1):

    for line in tqdm(f, total=total_lines, desc="Processing lines"):

        parts = line.strip().split(",")