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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 require_exp_directory(f):
 """Decorator to verify that a command is run inside a valid Dallinger experiment directory. """

    error = "The current directory is not a valid Dallinger experiment."

    @wraps(f)
    def wrapper(**kwargs):
        if not verify_directory(kwargs.get("verbose")):
            raise click.UsageError(error)
        return f(**kwargs)

    return wrapper