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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def watch(ctx):
 """Watch the directory for changes. Automatically run tests. """

    vcs = ctx.obj['vcs']

    event_handler = TestsEventHandler(vcs)

    observer = Observer()
    observer.schedule(event_handler, vcs.path, recursive=True)
    observer.start()
    click.echo('Watching directory `{path}`. Use ctrl-c to stop.'.format(path=vcs.path))
    while observer.isAlive():
        observer.join(timeout=1)