Gets the font face that this scaled font uses. This might be the
font face passed to cairo.global.scaledFontCreate, but this does not
hold true for all possible cases.
The #cairo_font_face_t with which scaled_font was
created. This object is owned by cairo. To keep a reference to it,
you must call cairo.scaled_font.ScaledFont.reference.
Gets the font face that this scaled font uses. This might be the font face passed to cairo.global.scaledFontCreate, but this does not hold true for all possible cases.