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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(self, inp):
 """Converts a string representation of some quantity of units into a quantities object. Args: inp (str):
 A textual representation of some quantity of units, e.g., "fifty kilograms". Returns: A quantities object representing the described quantity and its units. """

        inp = self._preprocess(inp)

        n = NumberService().longestNumber(inp)
        units = self.extractUnits(inp)

        # Convert to quantity object, attempt conversion
        quantity = pq.Quantity(float(n), units[0])
        quantity.units = units[1]

        return quantity