code: def decompose(self, q):
          
          try:
              ptype = q.unit.physical_type
          except AttributeError:
              raise TypeError("Object must be an astropy.units.Quantity, not "
                              "a '{}'.".format(q.__class__.__name__))
  
          if ptype in self._registry:
              return q.to(self._registry[ptype])
          else:
              return q.decompose(self)
docs: A thin wrapper around :meth:`astropy.units.Quantity.decompose` that
          knows how to handle Quantities with physical types with non-default
          representations.
  
          Parameters
          ----------
          q : :class:`~astropy.units.Quantity`
              An instance of an astropy Quantity object.
  
          Returns
          -------
          q : :class:`~astropy.units.Quantity`
              A new quantity, decomposed to represented in this unit system.