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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 preprocess_xarray(func):
 """Decorate a function to convert all DataArray arguments to pint.Quantities. This uses the metpy xarray accessors to do the actual conversion. """

    @functools.wraps(func)
    def wrapper(*args, **kwargs):
        args = tuple(a.metpy.unit_array if isinstance(a, xr.DataArray) else a for a in args)
        kwargs = {name: (v.metpy.unit_array if isinstance(v, xr.DataArray) else v)
                  for name, v in kwargs.items()}
        return func(*args, **kwargs)
    return wrapper