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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 ensure_dtype(func, argname, arg):
 """ Argument preprocessor that converts the input into a numpy dtype. Examples -------- dtype('float64') """

    try:
        return dtype(arg)
    except TypeError:
        raise TypeError(
            "{func}() couldn't convert argument "
            "{argname}={arg!r} to a numpy dtype.".format(
                func=_qualified_name(func),
                argname=argname,
                arg=arg,
            ),
        )