Textmate-style isoD snippet for SublimeText

isoD.py

import sublime, sublime_plugin
from datetime import datetime

class TimestampCommand(sublime_plugin.EventListener):
    """Expand `isoD` to YYYY-MM-DD."""
    def on_query_completions(self, view, prefix, locations):
        if prefix == 'isoD':
            val = datetime.now().strftime('%Y-%m-%d')
        else:
            val = None
 
        return [(prefix, prefix, val)] if val else []