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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 asbaseline(self, pos):
 """Convert a position measure into a baseline measure. No actual baseline is calculated, since operations can be done on positions, with subtractions to obtain baselines at a later stage. :param pos: a position measure :returns: a baseline measure """

        if not is_measure(pos) or pos['type'] not in ['position', 'baseline']:
            raise TypeError('Argument is not a position/baseline measure')
        if pos['type'] == 'position':
            loc = self.measure(pos, 'itrf')
            loc['type'] = 'baseline'
            return self.measure(loc, 'j2000')
        return pos