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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 convert_units(self, desired, guess=False):
 """ Convert the units of the mesh into a specified unit. Parameters desired : string Units to convert to (eg 'inches') guess : boolean If self.units are not defined should we guess the current units of the document and then convert? """

        units._convert_units(self, desired, guess)
        return self