@staticmethod
def map_sf_to_greek(sf):
    """Render scale factors in Greek alphabet if appropriate.

        Pass this dictionary to *map_sf* preference if you prefer µ rather than u.

        Example::

            >>> with Quantity.prefs(map_sf=Quantity.map_sf_to_greek):
            ...     print(Quantity('mu0').render(show_label='f'))
            µ₀ = 1.2566 µH/m -- permeability of free space

        """
    return {'u': 'µ'}.get(sf, sf)
