Poor man's stopwatch profiler for code blocks

stopwatch.py

import time
import datetime


class Stopwatch:
    def __init__(self, message: None, silent=False, callback=None):
        self._start = None
        self._stop = None
        self._silent = silent
        self._message = message
        self._callback = callback

    def print_message(self, message):
        if not self._silent:
            if self._callback:
                self._callback(message)
            else:
                print('Duration: {}'.format(message))

    def start(self):
        self._start = datetime.datetime.now()
        self.print_message(self._message)

    def stop(self):
        self._stop = datetime.datetime.now()

    @property
    def duration(self):
        return self._stop - self._start

    def __enter__(self):
        self.start()
        return self

    def __exit__(self, *args):
        self.stop()
        self.print_message(self.duration)