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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 get_checkout_command(self, revision, clean=False):
 """Get the command to update the working tree of the local repository."""

        command = ['hg', 'update']
        if clean:
            command.append('--clean')
        command.append('--rev=%s' % revision)
        return command