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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 disk_check_size(ctx, param, value):
 """ Validation callback for disk size parameter."""

    if value:
        # if we've got a prefix
        if isinstance(value, tuple):
            val = value[1]
        else:
            val = value
        if val % 1024:
            raise click.ClickException('Size must be a multiple of 1024.')
    return value