Python time converter

ptime.py

#!/usr/bin/python3 
from datetime import datetime, timezone
from zoneinfo import ZoneInfo
import sys

def convert_timestamp(input_timestamp):
    # Determine if the timestamp is in milliseconds or seconds based on its length
    # Assuming it's in milliseconds if it's greater than 10 digits (a common convention)
    if len(input_timestamp) > 10:
        timestamp_seconds = int(input_timestamp) / 1000
    else:
        timestamp_seconds = int(input_timestamp)
    
    # Create a UTC datetime object from the timestamp
    utc_datetime = datetime.fromtimestamp(timestamp_seconds, tz=timezone.utc)

    # Define the time zones to convert to
    time_zones = {
        "UTC": timezone.utc,
        "HST": ZoneInfo('Pacific/Honolulu'),  # Hawaii Standard Time
        "Pacific": ZoneInfo('America/Los_Angeles'),  # Pacific Time (supports DST)
        "EST": ZoneInfo('America/New_York'),  # Eastern Standard Time (supports DST)
    }

    # Convert and print the datetime in each time zone
    for zone_name, zone in time_zones.items():
        local_datetime = utc_datetime.astimezone(zone)
        print(f"{zone_name}: {local_datetime.strftime('%Y-%m-%d %H:%M:%S %Z%z')}")

if __name__ == "__main__":
    if len(sys.argv) != 2:
        print("Usage: script.py <timestamp>")
        sys.exit(1)
    print("p's time converter")
    convert_timestamp(sys.argv[1])