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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 min_abs(self):
        '''Returns minimum absolute value.'''
        if self.__len__() == 0:
            return ArgumentError('empty set has no minimum absolute value.')
        if self.contains(0):
            return 0
        return numpy.min([numpy.abs(val)
                          for val in [self.max_neg(), self.min_pos()]
                          if val is not None])